I was there Sunday/Monday. Sunday morning started with Splash down, came back up in time for my 12:20 FP+ and got to ride it. Monday morning same deal, started out of service, making the FP+ line for Thunder a NIGHTMARE. We got in line at 1:10 for a 12:20 - 1:20 and we didnt scan our MB until 1:25! it was insane. Splash came back up and then a little while later we walked by and saw them evacuating people off of it.
When we rode it on Sunday, there was an announcement to the effect of "a delay in boarding times is leading to a long delay in the queue". It seemed like they were using that to justify letting lots of FP+ in. Similar experience on Thunder and Space on Sunday too. I felt bad for standby...