This is an issue I experienced today and was able to solve ( in the end ) despite the fact that I couldn’t find any information about it.
So I decided to write it all down, so if someone, somewhere experiences the same issue some day, he/she might stumble upon this solution and not waste an hour trying to figure it all out.
Anyway, I was trying to pass an image path {thumb} to a plugin that crops the image to a desired size.
I tried both Imgsizer and CE Image. Both produced the same result:
instead of returning my <img> code they returned m20o93h7pq09l8x1t49chy01z5j4tt91fgfr
other error codes are:
M20o93H7pQ09L8X1t49cHY01Z5j4TT91fGfr
M30o93H7pQ09L8X1t49cHY01Z5j4TT91fGfr
M40o93H7pQ09L8X1t49cHY01Z5j4TT91fGfr
M50o93H7pQ09L8X1t49cHY01Z5j4TT91fGfr
M60o93H7pQ09L8X1t49cHY01Z5j4TT91fGfr
I couldn’t figure out what it was, but in the end it turned out to be amazingly easy to fix:
The plugins didn’t parse correctly because another plugin was acting up.
You can find out which one by enabling your template debugging:
admin > Output and Debugging Preferences > Display Template Debugging?
Apparently commenting a plugin :
<!-- {exp:plugin} -->doesn’t prevent it from parsing and throwing errors.
So I just removed the plugin code and all worked fine.