If you want an issue fixed, you have to play the semantic games. It's not my fault you don't know what you are doing.
A stumble at steady speed is not a surge.
I sure hope you don't give advice to people...
Could you please explain how and where your indicators were installed. electrically? I mean, did you splice wires or jump connections?
I am willing to bet that this is two different issues.
Indicator misbehaves on a completely stock system, running for minutes? OEM system flaw- most likely...
I am going to posit that your bike DOES NOT have a surge in the midrange, but actually has a flat spot.
The FTR has a flat spot between 3000 and 5500 rpm...
Rule of thumb....
"If it started before what I did, but it doesn't start now, what I did is the issue..."
That being said... a lot of what you say makes me think the battery voltage is low.