duplicated history entries at the same timestamp

For some time I had an issue with my history using GNU bash (version 4 and 5) where commands appeared in duplicates. I assumed this was due to the fact that in my .bashrc I had the following line: PROMPT_COMMAND="history -a; history -n; $PROMPT_COMMAND" and since I'm using terminal multiplexers (screen and/or tmux) the above mentioned command gets executed several times (therefore echo $PROMPT_COMMAND results in history -a; history -n; history -a; history -n; In some situations (especially when doing stuff concomitantly on different panes/windows/frames/buffers) the last command I entered was stored twice or even more often in my ~/.bash_history. This led to entries like the following: #1596110297 yadm list -a | xargs -t ls -l yadm list -a | xargs -t ls -l Needless to say, this is pretty annoying. I hoped I found a fix for the issue by changing the command to PROMPT_COMMAND="history -a; history -n but this did not solve it. Any ideas why that is the case and what I could do get rid of it? --- Disclaimer: I posted parts of this question at https://unix.stackexchange.com/questions/604842/grep-for-lines-not-after-a-pattern (since I thought the above mentioned solution would work and I therefore only wanted to only get rid of the duplicated entries).