Thank you for your reply. I opened my game now again to test around, first with mods + cc; the hashtag issue still occurs. Both trying to upload with hashtag and no text, or hashtag and more text, neither way works.
With mods/cc reinstalled and looking for more blank spaces etc, I had another issue: I had these two sims talking. After a while I realized she was still talking as if they were in a conversation (she was listening + responding "aha mhm oooh" and moving) while he was not even talking or moving at all, he was frozen. Tried to end the chatting or make them do something else but neither stopped - it's like they were stuck. I also noticed a glitch in the sky, but that still occurs without mods/CC installed. Don't know if that's how it's always looked from that angle and I just haven't noticed?
Now I removed the mods/CC again and restarted. The thing where the sim froze did not happen again. The sky is still glitchy. And, I noticed the mailbox has blank spaces. Also a notification on the wall about the mail being delivered is blank and there are some blank places when I click on it. (Several screenshots attached.)
So the issue may be even bigger than the hashtag. I have no idea what to do. What's the procedure to follow if it's an error?