Strange character replacement

For some reason when I paste an URL into a form field, the x character is transformed into a ×, so for example an URL ending in -150x150.jpg becomes -150×150.jpg breaking the link, this happens when rendering the fields into the mail template, if I write static URLs into the mail template this not happens.

I ended up by doing something like this: <img src="[cuttedImageUrl]-150x150.[extension]"> programmatically splitting parts of URL which works but is painful to replicate, also I’m not sure if this happens only to x or also to other characters and this would break the URL in the future.