Sudden Physics Simulation Lag

Hi, Ive been working on an Aircraft now for two weeks or so and up untill recently everything has been fine, plane flew with no major lag spikes nor issues. Of recent without any major script changes (which i’ve verified by inserting the exact unchanged version) I would be flying and Fps would suddenly drop from solid 60 to crazy 20s and 30s.

My aircraft uses constraints however they wouldnt cause the issues as for a year i’ve never experienced such an issue if it were them and deleting these doesn’t seem to fix the issue. Ive tried recoding and isolating the issue but it seems its nothing at all to do with code but possibly a recent roblox physics change.

I usually deal with these changes but this one is proving difficult and delaying my schedule. Ive done multiple microprofilers and they point to simulation as the primary lag spike issue. Runjob is high however a debug.profile check shows the scripts calling that run without high latency being 0.1-0.3ms range. I’ve heard others are facing the same issue around Roblox but Im not exactly sure if its been fully fixed. I’ve attached a profiler dump aswell as a small video showing the serverjob and issue unfold which displays simulation at almost 100x what the others are at. log_B0C24_microprofile_20200518-014802.html (229.6 KB)

Game Link Is:
If an Engineer needs a physical place file I can only DM that.

How many parts? If it’s in the mid thousands lagbursts are just a commonality of the physics being overworked. Seemingly happened more often for me when involving various disassociated physics modifiers on a mechanism. Terrain buoyancy and CustomPhysicalProperties, Contraints and the old school BodyForces. Just observation.

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Yeh my plane uses mainly hinge an spring constraints for the landing gears which are essential, before recent I had no issue with flying however it seems to lag spike now more often and out of the blue for longer durations. I removed a cockpit i recently added which seemed to slow down that spike.