Fire-Smoke effects floating bug

[IckyATLAS]

I use the summer Kuban Map and have an SP mission that is a very loaded and complex mission. Hundreds of objects, dynamic objects, ships, vehicles, trains, static and dynamic blocks, basically everything that can be done is in here. I have three groups of fire and smoke effects. Thess fire and smoke effects, consist of a mix of types of Static Fire, City Fire Small, City Fire. One group is located on the Town of Nijnebakanskaya, one is in the open field on the road and railway between Nijnebakanskaya and Vehrnebakansky, and the third and last one is on the Gelendzhik-2 airfield.

These fire and smoke effects are on ground and are at different altitudes as these three locations on the map have different altitudes. One group is at about 2mt another at 64mt and one at about 150mt.

Once in a while they find themselves all at about 350mt for the Y coordinate. They float in mid-air. It can be 355, another time 352 etc. But when this happens they have all exactly the same Y value.

There is a corruption that happens on the Y value and I do not understand why.

Here are some pictures:

 

 

 

 

 

 

If I reposition on the ground the effects then it may work but not always. If I cancel the groups and then import again the groups it does work.

But when I rework again the mission (never touch the effects as they are done in place and there is nor change) with the ME my effects jump again in the sky, and always around 350mt and all at the same altitude. The altitude will vary each time around 350mt by less than  +/- 10 mt and never more. This does not appear always immediately but after two or three mission change they start flying again. And this problem is only with the fire and smoke effects. All other effects do not have this problem. And fires or smoke that appear during the game they have no issue neither. Just makes me mad as I see absolutely no reason. And these three groups are completely independent as they connect to nothing in the game. They are self standing.