just bought a 2020 an400 on way home died. been in workshop for couple of weeks and now tell me the coil connections were corroded so new coil on order. The problem I had was it had driven faultless from the shop for about 70 miles then spluttered and stalled. after about 15mins it started ok but tickover for about 5min stalled again. it has the pattern now whether started from cold or warm and was originally though to be the fuel pump but pressure tests ok...does that sound like it could be the coil?
On FB group someone said it is a common fault?? are there any others I should know about?

Thanks for any replies in advance

As an ex-Burgman 400 owner & tech, I'm not aware of any "common" problems with this model. The mechanics of the motors are pretty much identical across the later years so folks can buy them with confidence. In fact, it's one of the most trouble free bikes on the market. I am retired now but still have my finger on the Burgman pulse. What someone may have been indicating to you is that they have had some issues with the coils on some 400's. A few years ago they had issues with voltage regulators on pretty much all Suzuki's but this was sorted quickly under warranty. This sort of issue can & does affect all makes of bike at various times. So don't be alarmed. It will be sorted.

And yes, a faulty coil can cause the exact symptoms you complain of.

Had a very similar problem (at least the symptoms) on my 2011.... only mine was at the plug end of the HT lead.... Problem showed itself as unstable running, poor tickover, occasionally engine dying.
Then it would be ok for months... and then do it again.
Eventually identified when it finally stopped alltogether whilst in the middle of nowhere requiring me to dissasemble at side of road.... turns out Spark Plug Cap had not been screwed onto the cable... being held in place only by the rubber boot... cable end had no hole in it (from where the screw in cap should have been). This must have been like this since new... so not so much a why it failed as how it worked for 10+ Years!.