I go for the pump noise, I have seen it happen on a jet Cat once, then again on both angines at the same time with two deferent brand radios, the pump was change and things were back to normal. Also if you did this at home there may be some new noise coming from a phone tower or some thing like that, defenitelly something has change since last time you run your engines at that spot.

Something is new at that sopt for it to happen to both systems at the seme time and with two diferent brand radios, the new Gaspar Fedec is probably filtering that noise where the old fedec couldn't. Did you try to run them at the filed or at home, do some research at home and report back ( I'm curious now ) you may be able to answer your question.

Good luck and have fun with you jets [8D].