Parts changing positions on quicksave

[edwin.robert]

Hello all

I am playing KSP 1.4.1 with DLC and I have encountered a new problem. I'm trying to recreate the Falcon heavy launch and what i'm doing is landing two boosters simultaneously using mechjeb. After separation, i use Mechjeb to activate land at target and select launchpad. It will do the boostback burn for both boosters and then i turn on land somewhere. But after quickloading with FMRS, the parts on one booster have moved around for no reason. Parts moved around include the gridfins, landing legs, airbrakes and a small fuel tank at the bottom, which i use as the octaweb. This is a huge problem as the gridfins change their position and the booster just spins uncontrollably and crashes. This only happens with one booster though. I have included pictures of the affected booster and the normal booster. Any ideas on what is going on? Similarly, a minimus science lab base i made in another game was also having this problem of parts moving around. 

Link to screenshots: https://imgur.com/gallery/NAJZ7bF

[swjr-swis]

4 minutes ago, edwin.robert said:

But after quickloading with FMRS, the parts on one booster have moved around for no reason. Parts moved around include the gridfins, landing legs, airbrakes and a small fuel tank at the bottom, which i use as the octaweb. This is a huge problem as the gridfins change their position and the booster just spins uncontrollably and crashes. This only happens with one booster though.

Are you using autostruts? This happens often when the autostruts reconnect after a staging, docking, or loading event, and the autostrut setting is ambiguous. Eg. when you have it set to 'heaviest' (the default) and at the moment of staging or loading the heaviest part is not the one you would expect, or there are multiple parts of identical weight that are not symmetry partners.

[edwin.robert]

Yes I do have autostruts activated. They're all set to Grandparent part using the Editor Extensions Redux. Should i change them to other autostruts and test them? Thanks for the quick reply though!

[swjr-swis]

48 minutes ago, edwin.robert said:

Should i change them to other autostruts and test them?

Examining the screenshot closer, it looks like you have the gridfins attached to the nose cone. If you have autostruts on those fins, try disabling them, or attach them to the booster tank instead.

[edwin.robert]

3 minutes ago, swjr-swis said:

Examining the screenshot closer, it looks like you have the gridfins attached to the nose cone. If you have autostruts on those fins, try disabling them, or attach them to the booster tank instead.

The gridfins aren't attached to the nosecone but it looks like it though. Im currently testing it out without autostruts. Hope it works!

[edwin.robert]

Unfortunately it didnt work, not even on another game. I just landed on minimus on my career save and the core fuel tank slided off and it exploded. 

[swjr-swis]

1 hour ago, edwin.robert said:

Unfortunately it didnt work, not even on another game. I just landed on minimus on my career save and the core fuel tank slided off and it exploded. 

That really should not be happening, not even in a stock game without autostruts.

You mention MJ and FRMS, so you are playing a modded game, correct? If you're not using it yet, perhaps KJR can help.