Paper b1618 (1.12.2)
Spark b133

I can confirm it shows at least on Paper 1.15.2
(don't know about 1.13-1.14)

The relevant Paper patch was only introduced in the late 1.13.2 era. Tracking MSPT without an explicit tick start/tick end patch is difficult (since without NMS or mixins, we can only use the Bukkit scheduler, which is not accurate).

If you are willing to modify your server JAR, here's a patch that we made against Paper 1.12.2 for our fork.

I think I may close it as problem is solved, thanks @astei for tip & patch!