Multi-currency transactions with trading accounts from 2.4.13 getting messed up in latest 2.6.3

[Mark]

   Hello,
   I am having problems with my old gnucash files and some of the
   multi-currency transactions in those files.
   I am using trading accounts and have transactions with USD and EUR
   accounts that handled through respective trading account splits.
   So far, I was using 2.4.13
   I just installed 2.6.3 on a new machine and loaded the old gnucash
   files.
   Some of my transactions now have a 5th split with one of the IMBALANCE
   accounts (EUR or USD) added and one of the amounts of the trading
   amounts messed up.
   Loading the exact same file into 2.4.15 works fine (exactly as in
   2.4.13).
   What could be the problem here? Is this a known issue? If not I will
   send a sample transaction...
   Thank you...