What version of Photoshop are you using?
Also, does the issue look something like this, or similar? - Photoshop brush not releasing (iPad Pro)
Is there a Wacom driver installed on your Mac? If so, what version number?
Any other third-party plugins or drivers installed on your Mac?
Something to try, is reset Astropad to default-
Close Astropad’s Mac app.
Then hold Option/Alt key while opening the Mac app again.
It will ask if you want a factory reset.
Also, maybe try resetting Photoshop’s preferences to default -
hold Option+Command+Shift as you start Photoshop.
Current settings will be deleted.