Multiple consecutive spindown attempts on same disk - trouble ahead?

[gordongraham]

One of the disks in my array (disk 4) sometimes takes multiple attempts to spin down. The rest do so no problem. The usual "click" when spin down is successful (all my disks make this sound) happens over and over until it succeeds.

 

Spin-up groups are already disabled.

 

Should I be worried and make steps to swap the disk out? Any advice appreciated. Running 4.7 and Syslog attached.

log3.txt