PT 7.3 crash in multi tempo session when moving tracks left

[koko]

Helloa, hello, hell...

I had a session with no plug-ins and two tempos from PT 5.1.3, MacOS 9. Opened this in HD3, PT 7.3.1, MacPro 2.66 GHz 4 GB RAM, MacOS 10.4.8. Grouped tracks as "All", made an edit and tried to move a couple of bars of 20+ tracks just 4 bars to the left in the second tempo range.
PT folded into a Crash report - crashed thread with start address change.

So I deleted the databases, prefs et al and made a new session in 7.3.1, imported tracks from old session, made a new tempo map, made a Save Copy of this session to a different disk. Emptied trash, restarted the CPU and 192 Digital I/O

Reopend PT, opened new session and crashed when moving 20+ tracks 4 bars to the left

Repeated crash recovery procedure and reopened new session. Moved 20+ tracks 4 bars to The RIGHT - no crash.
Made some more edits and moved tracks to the RIGHT- no crash
Made some more edits and moved some tracks to the LEFT - CCCRRRRASSHSHHSHSHHHSHHSH

Finished editing by moving and duplicating tracks to the right of the timeline - everything went without any problems
As soon as I tried moving multiple tracks left - crash

My HD3 system, apart from Kernel Panics caused by mTools, is solid. It delivers 12+ hours a day, every day for a couple of months now.

Has anyone experienced such editing problems ?