[MC-38100] Occasional random stuttering (root.tick.level.chunkCache.recheckGaps)

I am getting stuttering for a few seconds at a time in what appears to be random places in the mine of our SMP server. When I get stuttering, the following appears in the log:

[Client thread/WARN]: Something's taking too long! 'root.tick.level.chunkCache.recheckGaps' took aprox 534.087368 ms
[Client thread/WARN]: Something's taking too long! 'root.tick.level.chunkCache' took aprox 574.113264 ms
[Client thread/WARN]: Something's taking too long! 'root.tick.level' took aprox 576.275117 ms
[Client thread/WARN]: Something's taking too long! 'root.tick' took aprox 577.2218 ms
[Client thread/WARN]: Something's taking too long! 'root' took aprox 585.468536 ms

So far I have found no correlation with other people being on or doing specific things.