Thread:Extension talk:Scribunto/'Equal' character used in template parameter messes things: bug or feature?

Hi, when is "20px" the value is passed to the module as a "20px" string, just as expected. However, if in the same parameter you introduce "size=20px" then what you get is still a " " string, as if no value was introduced in this parameter of the template. I have been trying to use tostring trying to convert that "=" in just a character, but nothing that I've done works. You can see the problem live at https://test2.wikipedia.org/wiki/Module:Sandbox/QuimGil/FlagTranslations/doc. The first 4 flags render correctly but the fifth (where "size=" is used keeps showing a "  ", just like the rest of flags with no second parameter). Is this a bug or a feature? I'm printing the value of the variable next to each flag for debugging. The template is https://test2.wikipedia.org/wiki/Template:FlagiconLua and the module https://test2.wikipedia.org/wiki/Module:Sandbox/QuimGil/Flagicon. You can edit those at will, I'm keeping the "stable" versions at en.wiki.