Firstly, take comfort in that Avast is actually
blocking some network traffic.
Secondly, note what ports and IP addresses are involved: You should be able to determine what IP addresses belong to what on your private network.
I've personally never seen one item I've highlighted show as my router automatically prevents port 138 from going out. See attached below:
I suggest scanning your system with this GRC site and report back what, if anything, GRC finds:
https://www.grc.com/intro.htm(Click the ShieldsUp logo to proceed>Hot Spots>ShieldsUp). This test is good for TCP transmission protocols only. It does not test UDP protocols.
--> Other than the one entry noted, everything else looks ok. Avast is blocking.