Folks, this just started yesterday. Engine just cuts out when I back the throttle right off, e.g. stopping at lights. Idles fine when cold. After it cuts out I can start it easy if I hold the throttle open a bit. 2014 EFI twin cam motor, bike is bog stock, except slip-ons. 30,000 km.

give the IAC valve a clean.  they can get stuck / gummed up and cause all sorts of issues and is responsible for maintaining idle
do a google search, its a pretty easy procedure

Thought it was the Idle Air Control Valve. Discovered air filter very oily and dirty. Replaced air filter. Sensors and probes in the air intake all dripping with oil. Cleaned all with throttle body cleaner. Bike hard to start after that but idles OK. Still need to take for a good test ride.

If you still have trouble, try changing out the VSS. Had problems with my wifes Slim for ages with very similar symptoms to yours. Changed every sensor in the intake circuit but nothing helped. Ended up changing out the VSS and havent had a problem since. Thing that threw us off was that none of the things that indicate  a faulty vss were happening. Speedo, indicators etc were all working normally. I had a thread about it on here somewhere.