No, nothing to do with poor communication, and whilst you and I know that there are diagram errors from time to time (I believe your Reigate/Three Bridges service a little while back was a case in point), reverting to the strike timetable (and randomly printing and distributing the thousands of special diagrams now associated with it, complete with different diagram numbers from what's on the master roster) would be a completely different scale of error.
Trains were unable to call at Merstham and Coulsdon South on the Up Slow for quite some time due to the Up Fast & Quarry all the way from Gatwick Airport, through Earlswood and up to Stoats Nest Jn being blocked. This was due to a points fault on the Up Fast at one end of Earlswood Station meaning that a MOM had to come out, block the line and clip the points in the middle of the peak, in order to work round the problem safely for the rest of the day. Because some of the area around Earlswood station, including the track around the disused Fast platforms, is a "Red Zone", assessments of the situation showed they could not proceed safely onto the line without blocking it, which also of course included all movements from Gatwick right through to Stoats Nest.
In reaction to this, some trains needed to skip Merstham and Coulsdon South to prevent fast peak expresses from being held up behind. Realistically this could be the difference between losing one or two paths at the very height of the peak, per train stuck behind a stopper, which is catastrophic for BML reliability at the best of times, let alone the fact that service was already being recovered after a points failure near Eastbourne and a failed train at Crawley requiring examination by fitters. AIUI Control were very well aware and inundated with calls asking why, but they did put the calls back as soon as the points were clipped and the Up Fast (and, by extension, the Up Quarry) reopened. Merstham and Coulsdon South, especially off peak, usually feel like quite quick stops, but with rush hour traffic and perhaps if services were thinned out rather than eliminated, which would have resulted in time-consuming overcrowding, they can cause a big queue very quickly. In turn, of course, this can cause queues past Earlswood affecting permissive working at Redhill, GWR service problems which could impact on a substantial part of the day, etc.
I'm afraid I can't comment on the provision of onboard information this morning, though.