Thank you for pursuing this and posting the results.
Actually, because I'm spending the summer working on questions to use with students, I've slipped behind with checking Maxima versions, so you are a little ahead of me here. I'll try to make sure I check Maxima 5.31.3 before the next teaching session starts in Sept.
I'm also going to try to streamline the process of creating the optimised memory image, but this might have too many server specific settings to work reliably. I'll try.