Basically, there is a terrible bug for the Eldar webway system. It can happen quite easily and remains for the duration of the game, removing one of the most important aspects for Eldar game play.
Upon hitting T2, you are able to connect two buildings together through the webway, allowing units to teleport between them. Anytime you relocate one of the connected buildings, the link is temporarily broken during the relocation transit. Upon reaching destination, buildings automatically reconnect after a few seconds. During the relocation time, the button for all buildings is grayed out stating "cannot use while relocation is active". Once the system automatically reconnects the building/s after transit, the ability becomes usable again on all buildings.
However. If during the relocation process a building connected through the webway is destroyed, the system will NOT release the button for use again, simply because the building never finished it's relocation. Since that building is destroyed, it will NEVER finish relocating, so the system cannot automatically re link them after transit, therefore for the rest of that games session, you cannot link ANY of your buildings together again.
This bug has happened to me a few times before. It wasn't until my recent game did i realize the occurrence was a bug.
I can imagine it happens very often considering the whole idea of the webway connection is to be able to get units away from/into dangerous situations so it's likley that people will attempt to relocated the connected structure and even more so that it will be destroyed.
This in my opinion is very game breaking as it removes one of the core tactics from the Eldar. Especially during mid-late when fast strikes on objectives and flanking opponents is key. Or to move your heavy, slow wraithlords around the battle.
I'm sure the fix is quite simple, just making sure the system understands that a building cannot finish relocation if its destroyed.
Thanks for your time!