introduced in D2322 backport
Didn't affect most people, only those who had custom fee selected (which required using Coin Control)
Workaround for affected users: change nCustomFeeRadio=1 to nCustomFeeRadio=0 in the ~/.config/BitcoinABC/<whatever>.conf file.
same fix was also required in core: https://github.com/bitcoin/bitcoin/pull/11332