If you've experienced excessive memory use, I'll need to see what memory is allocated to be able to resolve the issue. Luckily, macOS comes with a tool to capture this information.
Please run this command next time you see it taking a lot of memory:
heap -s -guessNonObjects -showSizes pid > /tmp/heap.txt
where pid is the process ID of iTerm2. There will be many processes name iTerm2, but look for the one in activity monitor that has an icon next to it). After running the command, attach /tmp/heap.txt to an issue.