Synth1 64b crashes on Mulab 7.7.4

[Paljas]

No obvious message in the log file at time of crash.
It seems to load OK, plays even for a bit, but crashes Mulab within a few seconds.
I haven't tested on a newer version as I'm on a v7 license.
Running on W10, Ryzen 3600, over ASIO driver.
32b works fine.
64b version of Synth1 runs fine on other DAWs (only tested in Waveform).

Any ideas (apart from obvious workarounds like run at 32b - have my reasons.. some plugins I want to combine in the same arrangement are 64b only)?

[MuTools]

It's a know issue in Synth1.
Pls contact the plug dev.