First, I’m an Avast user and not an Avast Team member.
You don’t say what Avast Program and version number you are using ?
A screenshot may help to get a better understanding. They should be periodically removed by Avast as new VPS updates come in. Avast would probably protect against these being moved manually.
I generally have a few, usually the current, previous and the Streaming updates for Virus Pattern Signatures.
The previous one is empty, the current one
You could try a system restart to see if that clears some of the debris.