The recommendation is to use the latest Stable release, in this case 4.4.8. For Krita 5 you can see that it has the Beta ‘title’, so it for testing and report bugs before the final release. These kind of problem are somewhat expected.
If you want you can follow the topics bellow to see in more depth the Bugs currently reported in Krita 5 Beta.
Krita 5 beta1: Brushes don’t work like they should from bundles
First Beta for Krita 5.0 released
Cheers.