When we place text from a Word file, we always strip it of all existing layout. But for some reason there are some weird unicode characters that cause Indesign to make certain words bold... I'm not able to figure out why... you have a French text where a word starts with a e with an accent like ê and that word is suddely bold... even though in the Word file it isn't.

This also happens with Italics... I once had a text that used transliteration for Ancient Egyptian that is in italic and often starts with a "Ankh" symbol: Ꜥ with the full hiëroglyph being translated as: Ꜥ-n-ḫ.

Indesign will flip out on this... in the end we had to replace all the Ankh symbols for @ symbols, place the text to Indeisgn and switch them back.

Also had it once for Greek text, where words randomly become bold or italic after you place them in Indesign.

When these symbols are in the middle of words, it's fine, but when words start with these symbols, weird stuff tends to happen when you place them in Indesign. Has been doing that for years. It's weird.