Bike wouldn’t accelerate past 50mph

I drive a 2008 Kawasaki Vulcan 900 classic with about 30,000 miles on it. On my way home today I noticed that I could not accelerate past ~50mph while in fifth gear. I shifted down to forth then back to fifth to see if that would help but it didn’t. It continued to max at ~50mph until I stopped for a red light. After waiting for the red light, the bike accelerated just fine on all gears. This is the second time this has happened however, the first time happened at least a month ago and the bike maxed out somewhere between 20-30mph. Does anyone know whats going on? Is the bike just getting older? Its been garage kept most of its life and I’ve ridden it almost everyday for 10 months. In these 10 months I’ve put about 10,000 miles on it. Is this a sign of a repair that needs to be made? Any suggestions would be much appreciated! via /r/motorcycles https://www.reddit.com/r/motorcycles/comments/fb84xc/bike_wouldnt_accelerate_past_50mph/?utm_source=ifttt