I may be doing something wrong. Si to check first. Flight plan EGLL/KSFO. I edited the the approach and added some speed constraints. One was for 220kts.

 

take off and climb and I was stuck at 220kts throughout. I had to manually control speed. It wasn’t until I deleted the speed constraints at the end of the flight plan that things returned to normal.

in hope this makes sense. Have I done something wrong or is this a possible glitch?

Hi. We don't quite understand the issue as you describe. Can you possible share a video or an autosave of after you input the constraints so we can take a look? 
Thanks.