I think I know why this is.
We rely on spaces in sentences to distinguish between words, as does code that manipulates strings, such as sprintf. It will understand to replace a variable like %s, for example.
Thai is one of those languages that does not use spaces, as the vast majority of words are monosyllabic and are just differentiated by different tones. This is normal for tonal languages. Crazy, right?
Ok, so then people can use Google Translate to translate many strings in Loco Translate, and GT just creates a sentence without spaces in Thai and plops the %s right in the middle of it.
This can cause problems in certain cases.