Heavy performance degradation after exporting data with mongodump


I am currently facing an interesting issue. Instance M10, 6k documents in one database. Exporting bson using mongodump. Export is OK, BUT after it, Atlas starts to behave “strange”

CPU usage on P node stays on 30% (normally 3-10%), and network outgoing traffic remains at 2-3MB/s (normally 100-400 kb/s), despite the fact, that export is finished and no mongodump processes are running on client machine (windows).

It happened twice today, 1st occurence caused the P->S switch, since DB was almost unresponsive.

Any idea, what can cause this ?