Describe the bug
When pushing rolling stock, weather this be reversing or just pushing stock, there is a high chance of the stock merging together atleast one piece of stock back, appears to be most frequent when using coaches, however i could not seem to recreate it using freight stock, but this may be down to the type i used (my own 16T mineral wagons from my freight pack) as they are small wagons

Length appears to be a part of this as if the coaches are small - say 1-2 MK1s issue doesnt occur, however when using up to about 5+ issue is extreamly common, appears to happen most around switches and on slopes, however have had it happen on all types of track.

Issue can be avoided if both the front and rear of the train are loaded, say if in multiplayer a person is sitting at the back of the consist, even if the middle of the consist is unloaded due to length (tested with my own MK2 coaches with over 30, as long as the rear was loaded we had no issues reversing)

How to reproduce
Steps to reproduce the unwanted behavior:

1. get a train of more than 2-3 coaches
2. attempt to push the coaches for a reasonable distance, (it was rather random if it decided to jump instantly or after a decent bit of travel)
3. result?

Expected behavior
A clear description of what you expected to happen.
Coaches and locomotive reverse without issue

Screenshots
If applicable, add screenshots to help explain your problem.
Locomotive + coaches before reversing:

Locomotive + Coaches after reversing a short distance, stopping, then reversing again (unlikly the stopping had a part):

Stock appears to merge one coach back at a time, and if continued reversing can merge further
Render distance was at 16

Could not re-create the issue when using freight stock, but may be down to the smaller size wagon i used as explained at the start, used nearly 100 of these wagons and had them down well out of my render

System Information
OS: Windows

16GB

Allocated Memory: 8GB

CPU: AMD Ryzen 3 2200G 3.5GHz Quadcore

GPU: GeForce GTX1050TI

IR-Version: 1.8.0 1.12.2

Forge-Version: 14.23.5.2854

Modlist
Provide a list of the mods you used. You can either directly write them in here or use an online service like https://pastebin.com/ and provide the link.
A little exta tiles
Creative core
Dynamic Trees
Dyamic tress Biomes O Plenty compatability
FTB Utilities
Immersive technology
JEI
Little Tiles
Terrarium
World Edit CUI
Forge edition 3
AutoRegLib
Betterbuilderswands
Better foliage
Biomes O' Plenty
Building Gadgest
Chisel
CoFH Core
Connected Textures Mod
Dynamic Surroundings
Fast Leaf Decay
Flat coloured blocks
FTB Libarary
Immersive Engineering
Immersive Petroleum
Immersive Posts
Immersive Railroadiong
Journeymap
Mouse tweaks
OreLib
Quark
Redstone Flux
Shadowgfacts Forgelin
Track API
Universal Mod Core
Worldedit
latest.log
Provide the latest.log by going into your Modpack_folder/Logs, paste the contents of the file to an online service like https://pastebin.com/ and provide a link.
https://pastebin.com/Q8MqnNV0
Additional context
Issue appears to be somewhat related to the stock never being fully loaded if you are at the front, even if it starts moving, ive noticed very. very. funky movement when traveling at high speed of the coaches behind of them almost "dancing" as they move faster and slower merging weirdly.
Issue is prevelent on both singleplayer and multiplayer with compeatly different modlists and resource packs enabled.

issue does seem to be somewhat more common on some stock than others, as ive noticed it extremaly common on my british MK2s from my modern british pack, but seemingly rarer on some of brums dutch stuff- however this may be down to my own bias as i use my own coaches more often