KDE applications fail to start with the following error:

symbol lookup error: /usr/lib/libKF5QuickAddons.so.5: undefined symbol: _ZNK19KCoreConfigSkeleton10isDefaultsEv

The affected applications I’ve found so far are:
dolphin 19.08.3-1.0
kwin 5.17.3-1.0
plasma-workspace 5.17.0-2.0

After downgrading kdeclarative to 5.63.0-1.0 kwin and plasma start but dolphin fails with a new error:

dolphin: symbol lookup error: /usr/lib/libKF5KCMUtils.so.5: undefined symbol: _ZNK12KQuickAddons12ConfigModule11errorStringEv

Downgrading kcmutils to 5.63.0-1.0 finally fixed dolphin.