We've had an issue like this and it came down to changes in layer combos. Graphisoft are aware of it and it will be addressed in the next public hotfix. They suggested changing to a 'custom' layer combo before sending and receiving if changes have been made to the layer combo. I just reshared the project (which is strongly recommended any time you experience a problem with a TW file), and instructed the project's model manager to make all changes to layer combos only and follow the GS instructions, at least until the next hotfix.
This may or may not be the same problem you're experiencing, but if it were me I'd have everyone leave then save it as a pln and reshared it on the BIM Server, replacing the existing one.
Cheers,
Link.