Updating this with telemetry data png that I used to describe this. This is from Iko Rein's telemetry software. Note the following I posted in another thread - but this describes the problem in more detail:
I have been having this problem across a variety of tracks in career and in time trial. It looks like it started under version 1.6. I have included a png file of part of a spreadsheet generated from Iko Rein's telemetry software. This is data from the last long straight at Miami. It shows the car at 100% throttle in 7th gear and suddenly the brakes come on slightly - while I am still at 100% throttle. The brake percentage increases to 5% as I shift up to 8th, and the brake percentage falls back under 5%. My speed is at 287kph where it stays despite still being at 100% throttle. I cross the DRS line and engage it - and now the speed slowly begins increase again. As I approach 292 kph the brake percentage jumps to 5% and the DRS disengages. The brake percentage now continues to increase reaching into the teens. Note the far right column says I am still in the DRS zone. The revs start to fall eventually get under 7800 while in 8th (not on the part of the spreadsheet in the png). The other track where I match up with you in having the same experience is China - in the last long straight - but I have also experienced this in the last straight that crosses the finish line.
One other note - currently have been having difficulty with Spa - and have a couple of lap spreadsheets showing the same thing.
