This happens only when Parallel Import is enabled.

How can we reproduce it

(make sure that you have local Accelerator running on your computer)
1 Go to your Accelerator cache folder and open "cachedb" folder - it should contain only bbolt.db file, if it contains a folder - delete it (Note this will delete your Accelerator cache)
2 Create new HDRP project
3 Open menu Edit->ProjectSettings->Editor tab and:
3.1 Enable "Parallel Import" in Asset Pipeline section
3.2 In Cache Server section set Mode to Enabled, and set IP address to 127.0.0.1 (as you are using local Accelerator). Then uncheck Download and Upload
4 Close Editor Settings, go to Project Browser and do RightMouse->Reimport All then select either "Reimport" or "Download from Cache Server"
5 Wait while project is reopened
6 Go to your Accelerator cache folder and see that "cachedb" folder contains a folder which is around 600Mb

Actual results: Accelerator cache has big folder with cache, what means that artifacts were uploaded to Accelerator even while Upload is disabled in settings

Expected results: artifacts should not be uploaded to Accelerator. Cache should have a folder which is less than 1 Mb

Reproduces: 2021.2.0b12, 2021.2.0b15, 2022.1.0a12
Not reproduces: 2021.2.0b4