Out of the blue, one of my modules (as far as I can tell) began double encoding URLs...

So, instead of inserting a '%20' for a space, it would insert that, then encode the % sign as '%25', leaving me with a '%2520', which is non-functional.

Manually remove the 25 from the URL string, and it works just fine.

Any idea why this would happen, or what I can do to fix?