I don't know if it's the same bug but I save the joined file with IBM850 encoding and each time I open it, the encoding is ISO-8859-1 and some characters are wrong like ê that becomes . It's like Geany doesn't detect the right encoding.
[LISEZMOI.TXT](https://github.com/geany/geany/files/11017089/LISEZMOI.TXT)