No it is not a normal behaviour not unless you have tightened your security parameters somewhow.
For installing software, since installers are essentially just scripted archives that frequently extract files to one or more temporary locations during install, excluding them preemptively can be difficult if not impossible so the simplest solution would be to temporarily disable the Malware Protection component in Malwarebytes or temporarily turn off detection for PUPs (Potentially Unwanted Programs), install the software, then perform a Threat scan with Malwarebytes via the Scan Now button located on the Dashboard tab in the main Malwarebytes UI. Once the scan completes, click the checkbox at the top to uncheck all detected items, making certain that all of them belong to ASC (you obviously don't want to accidentally exclude any actual threats) then click Next and once the prompt is displayed asking what to do with the remaining/unchecked items, click Ignore Always and the program's files, folders and registry data will all be excluded from detection in the future, that is assuming your existing exclusions do not already cover the beta installation (a new program version means they might have changed one or more items/locations, so new exclusions may be necessary).
In the future, follow the same procedure of temporarily disabling Malware Protection or PUP detection in Malwarebytes whenever you are going to run an installer which is detected as PUP by Malwarebytes.
I hope this helps.