A quick followup.
The solution that has worked (so far) for us was to run the the task
Repair - Reconcile component database from blob store.
Our blob store was about 450 Gb and the task took 130 hours to complete.
After that we have not seen orientDB warnings about browse_node_2.pcl
As a general maintenance task we are planning to clean out a lot of old and unused artifacts from our repository in order to get a more maintainable size of our blob store.