This behaviour is one of the reasons I stopped exploring Indi/Ekos/Kstars. However, due to the sky model build process which is much better than in any other software, I have decided to give it another chance.
Last night I have tested it again. I have removed the sounds but it keeps crashing after solving with internal solver, regardless the method.
The only way it does not crash is if I "Sync" instead of "Sync and Slew". It looks like it is able to solve and when it will try to slew, it crashes. Maybe this information helps checking the code.
I am using AZ GTi in Alt AZ mode, using the Skywatcher Alt Az driver.
By using ASTAP it does not crashes but is much slower and has a higher failure rate.