On the freeze, the "how to report issues" page shows how you can generate a minidump for a frozen Max. This sounds different than the previous Bloom and Glare issue, which was a freeze while calculating Bloom and Glare at render end rather than anything that only happens during the save. One thought would be to save to CXR or EXR, without bloom and glare, and open in CIE and apply it there (and see if it lets you save).
Another thought, what file format were you saving to, and does changing that make any difference? Thanks!