Newsletter with erros without configuration/code changes

Hello,
I’m using your Automated Extension, in which I’ve created two channels: one for the portuguese newsletter (PT) and the other for the english version (EN). I’m using the qTranslate-X plugin to translate the contents. As such, I’ve created the following method to show the right text excerpt:

function GetLanguage($startString="",$endString="",$str){
    $temp1 = strpos($str,$startString);
    if ($temp1 !== false) {
		$temp1 = $temp1 + strlen($startString);
		$result = substr($str,$temp1,strlen($str));
		$dd=strpos($result,$endString);
    if($dd == 0){
        $dd = strlen($result);
    }
		return substr($result,0,$dd);
	}else{
		return $str;
	}
}

Example:
$text = “[:pt]Olá mundo[:en]Hello world[:]”;

GetLanguage(“[:en]”,”[:]”,$text); //Hello world
GetLanguage(“[:pt]”,”[:en]”,$text); //Olá mundo

So, the differences from the PT newsletter theme to the EN theme are:

English theme.php

<?php

function GetLanguage($startString="",$endString="",$str){
    $temp1 = strpos($str,$startString);
    if ($temp1 !== false) {
		$temp1 = $temp1 + strlen($startString);
		$result = substr($str,$temp1,strlen($str));
		$dd=strpos($result,$endString);
    if($dd == 0){
        $dd = strlen($result);
    }
		return substr($result,0,$dd);
	}else{
		return $str;
	}
}
(…)
<?php foreach ($new_posts as $post) { ?>

                            <tr>
                                <td>
                                    <br>
                                    <a href="<?php echo $post->link ?>"><img src="<?php echo $post->images['large'] ?>" style="max-width: 100%"></a> 
                                </td>
                            </tr>
                            <tr>
                                <td>
                                    <a style="font-family: <?php echo $post_title_font_family ?>; font-weight: bold; text-decoration: none; font-size: <?php echo $post_title_font_size ?>; color: <?php echo $post_title_color ?>" href="<?php echo $post->link ?>"><?php echo GetLanguage("[:en]","[:]",$post->title) ?></a>
                                </td>
                            </tr>
                            <tr>
                                <td style="border-bottom: 1px solid #ccc">
                                    <a href="<?php echo $post->link ?>" style="text-decoration: none; font-size: 14px; color: #000000; display: block; line-height: 1.5em">
										<?php echo GetLanguage("[:en]","[:]",$post->excerpt) ?>
                                    </a>
                                    <br>
                                    <?php if (!empty($read_more_label)) { ?>
                                        <div align="right">
                                            <a href="<?php echo $post->link ?>" style="text-decoration: none; font-size: 13px; color: #3570ba; display: inline-block; padding: 10px; background-color: white; border:2px solid #3570ba;text-transform: uppercase;font-weight: bold;">
                                                <?php echo $read_more_label ?>
                                            </a>
                                        </div>
                                    <?php } ?>

Portuguese theme.php

<?php

function GetLanguage($startString="",$endString="",$str){
    $temp1 = strpos($str,$startString);
    if ($temp1 !== false) {
		$temp1 = $temp1 + strlen($startString);
		$result = substr($str,$temp1,strlen($str));
		$dd=strpos($result,$endString);
    if($dd == 0){
        $dd = strlen($result);
    }
		return substr($result,0,$dd);
	}else{
		return $str;
	}
}
(…)

<?php foreach ($new_posts as $post) { ?>

                            <tr>
                                <td>
                                    <br>
                                    <a href="<?php echo $post->link ?>"><img src="<?php echo $post->images['large'] ?>" style="max-width: 100%"></a> 
                                </td>
                            </tr>
                            <tr>
                                <td>
                                    <a style="font-family: <?php echo $post_title_font_family ?>; font-weight: bold; text-decoration: none; font-size: <?php echo $post_title_font_size ?>; color: <?php echo $post_title_color ?>" href="<?php echo $post->link ?>"><?php echo GetLanguage("[:pt]","[:en]",$post->title) ?></a>
                                </td>
                            </tr>
                            <tr>
                                <td style="border-bottom: 1px solid #ccc">
                                    <a href="<?php echo $post->link ?>" style="text-decoration: none; font-size: 14px; color: #000000; display: block; line-height: 1.5em">
										<?php echo GetLanguage("[:pt]","[:en]",$post->excerpt) ?>
                                    </a>
                                    <br>
                                    <?php if (!empty($read_more_label)) { ?>
                                        <div align="right">
                                            <a href="<?php echo $post->link ?>" style="text-decoration: none; font-size: 13px; color: #3570ba; display: inline-block; padding: 10px; background-color: white; border:2px solid #3570ba;text-transform: uppercase;font-weight: bold;">
                                                <?php echo $read_more_label ?>
                                            </a>
                                        </div>
                                    <?php } ?>

The problem is: sometimes the previews and the respective newsletter in the English channel are with the texts in PT, which does not make much sense because the themes are assigned correctly and this doesn’t always happen. There are times when everything is ok in the preview and I receive the newsletter correctly. In other times, the text (title and excepert) appear in portuguese in the previews and, consequently, the English newsletter (without configuration changes).

https://ibb.co/imKAU6
Channels

https://ibb.co/eRTR2R
https://ibb.co/exEoGm
English Newsletter Channel

https://ibb.co/cnqjp6
English Newsletter (correct version)

https://ibb.co/hKOR2R
English Newsletter (with errors – title and excerpt text are in portuguese)

I don’t understand why is it hapenning. Please help me because the site is already in production.
Thank you.