Wrong temperatures

Another Glitch,
I have been flying the Neo around Rurope without problems then today.
Flying LHR to Sofia at 25, 000 ft EGT temp went wild 1500 deg engines shut down to 20% after 30 secs engine cooled down and engine ramped up again but plane was jumping around, then unable to climb engines all over the place.
Unable to correct this so made an emrgency landing.
Restrated pc tried again exactly the same- btw anti icing ok etc etc.
A ll settings were as normal- anybody had this one before??
Regards,
Sandy