Thank you for the confirmation, John.
Let us know whether you use AVG AntiVirus or AVG Internet Security and check the version of it.
Also, open Quarantine and send us a screenshot of it.
We're looking forward to hearing from you.
Hi John,
We are sorry to hear this.
We will help you to resolve the issue.
Did you get any error message from AVG?
If so, please provide us the screenshot of the error message to investigate further.
You can post the screenshot here in your topic. Click on "Answer" & then click on the "Image" [mountain symbol] & follow the instructions.
Keep us posted.
Hi Hendrik,
We're glad to look into this & help you.
Please write back to us in your own post, which will reveal the AVG account affiliated with us.
While writing back, please include the screenshot of the threat notification after clicking on 'See details' in it for better clarity.
Thank you for your understanding in advance!
Hi. I am experiencing the same issue. Furthermore, I don't trigger those flagged scripts myself and even today I am getting recurrent messages from AVG (as soon as I choose to quarantine, another warning pops-up). Again, a deep scan feature reports no threat.
Unfortunately, the attaching picture feature is not working on the website (once you click con the mountain icon, a little window pops up but it is unresponsive). So I have transcripted the contents of AVG's warning pop-up window:
Threat blocked
We've blocked tmp4i3dajp1.ps1 because it was infected with IDRALEXA.53
What would you like to do?
MOVE TO QUARANTINE - MORE OPTIONS
Threat name: IDP.ALEXA.53
File path: C:\Users\Jaime\AppDataXLocal\Temp\tmp4i3dajp1.ps1
Process: C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe
Detected by: Behaviour Shield
Since I rebooted and AVG updated, it's removing all of my powershell scripts, thinking they're IDP.ALEXA.53
I even wrote a quick one that says: Press any key to exit
and that was flagged too.
Is it only me?
Thank you for the confirmation, John.
Let us know whether you use AVG AntiVirus or AVG Internet Security and check the version of it.
Also, open Quarantine and send us a screenshot of it.
We're looking forward to hearing from you.
No error. just quarantined. Flagged as IDP.Alexa.53
Hi. I am experiencing the same issue. Furthermore, I don't trigger those flagged scripts myself and even today I am getting recurrent messages from AVG (as soon as I choose to quarantine, another warning pops-up). Again, a deep scan feature reports no threat.
Unfortunately, the attaching picture feature is not working on the website (once you click con the mountain icon, a little window pops up but it is unresponsive). So I have transcripted the contents of AVG's warning pop-up window:
Threat blocked
We've blocked tmp4i3dajp1.ps1 because it was infected with IDRALEXA.53
What would you like to do?
MOVE TO QUARANTINE - MORE OPTIONS
Threat name: IDP.ALEXA.53
File path: C:\Users\Jaime\AppDataXLocal\Temp\tmp4i3dajp1.ps1
Process: C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe
Detected by: Behaviour Shield
Same issue here and finally just added an exception. 
Hello Jorge.
It seems that the detection was from temporary file folder. I would request you to clean the temp files from your PC, restart your PC and verify if the pop up still appears.
Press the Windows Button + R to open the "Run" dialog box.
Enter this text: %temp%
Click "OK." This will open your temp folder.
Press Ctrl + A to select all.
Press "Delete" on your keyboard and click "Yes" to confirm.
All temporary files will now be deleted.
Hello David,
We're sorry for the inconvenience caused. We'll look into this further.
Have you tried the above-mentioned instructions?
Please write back to us in your own/new post, so that we can access your email address & send you an email with further instructions.
Kindly click on the "Ask the community" button to create a new post.
Then, type in your topic, issue description & proceed with posting your query.
Thank you for understanding.
Hi. I just did that and, as of now, have not received any nagging warnings. Thanks for your help
Hi Hendrik,
We're glad to look into this & help you.
Please write back to us in your own post, which will reveal the AVG account affiliated with us.
While writing back, please include the screenshot of the threat notification after clicking on 'See details' in it for better clarity.
Thank you for your understanding in advance!
I have exactly the same problem since a couple of days. When a run a .ps1 file with Powershell I get a message from AVG Antivirus for IDP.ALEXA.53 with the choice to quarantine or to create an exception. ALL .ps1 files are affected. A scan does not report any error. When I check the virusdefinitions version its is 210404-2, for the application it is 21.2.2455 - 21.2.67096.649.
Thank you for updating the status, Jorge.
We request you to keep monitoring the situation & if you encounter the same threat messages again, please contact us immediately.
We'll check & assist you accordinly. Keep us updated.
Same issue here and finally just added an exception.