Bricscad V21 crash changing annotation scale in model space

Hi, I have a new issue with Bricscad V21 (Mac OS X.15).
When I (try to) change the annotation scale in model space, Bricscad suddently crash down.
It happens in old files as well as new ones, as long as they have Xrefs. I use some of these files sometimes for weeks without trouble. It happened with a first one and then seems to propage to the others.
As long as I know no changes has been made in settings.
The same files works perfectly with Bricscad V16 (Mac OS X.11).

To be as complete as possible : I work in V21, I try to change the CANNOTSCALE and program shut down. Open the file on V16, I can use the file normally and change annotation scale - no trouble. Back In V21 I can, in the first opening, work with annotation scales but all dimensions are apparently in layer 0 and full white (when still in their correct layer in the properties window). I close the file, open it again, dimensions are back in their clean apparence but if I try to change annotation scale, crash again.

Do someone have any idea of what happens/wich settings may be blamed for ?

Thank you,
A.