Unusual Instrument Panel Indicator!

[Scouser]

Hi everyone, has anyone experience what I did yesterday?
I must admit I accelerated quickly from a gentle slope at a T junction onto a main road. Then without warning a Green number 13 appeared to the right of the D on the instrument panel. The car seemed to lose acceleration but recovered and drove normally. Since then it’s driven normally changing genres and decelerating. I drive a E Class 2018 220 AMG it’s only covered 36450 miles! There are no unusual smells so it’s not burning anything. I’ve never experience this before.

 

[onefortheroad]

Was it not ^3 . And you'd knocked it into manual with the paddles

 

[Scouser]

It’s possible because it was a tight turn into the main road. Normally never use the paddles!

 

[onefortheroad]

It's a green arrow pointing up. Telling you to change when revs rise. Try it .