Yes, this indicates the number of page faults in the previous 1 second. It’s perfectly normal for this to spike - it basically means something was read from disk. So loading a plugin, or opening a window for the first time and many other operations will make page fault spikes.
What you want to watch out for is, is spikes when you’re just “playing”. eg: if you’re using a large sample based library and you hit a note for the first time and the pf counter jumps - this might be something to look into.
Basically treat it as a possible indicator of problem.