So, this has changed now with the latest EN v10.3.7 & Avast all updated. I no longer get the Avast popup indicating that powershell has been blocked. Avast does not react at all as it did before. However, once the attachment opens (a spreadsheet), it crashes in the spreadsheet program in a few seconds & disappears from the screen. If you try it again, the spreadsheet goes into recovery mode successfully but crashes again in a few seconds. This is reproducible in v10.3.7 but does not occur in the legacy version. I am running the latest Win10 version 20H2 that was released this week.