There is no problem to have both red leads connected and in fact will provide 'redundancy' if one fails.
All my twin motor models have both reds connected ..... linear and switched BEC's.
Yes I know that Switched BEC's are supposed to not like this but - none of mine seem have any ill effect at all.
Personally - if the previous guy flew it with both connected - why change it ??
If the ESC's are separate channels - you have an added function if you want it ... differential throttle. You can set the mix so rudder action alters the motors to have different thrusts and create a turning moment ... (I do this with my models to help turns ... )