System properties like External forgot password URL, External login URL and External logout URL do not work, if they are applied under resellers with different configuration under provider.
POA-108606 - for External forgot password URL
POA-111638 - for External login/logout URL
The only workaround is to have a single configuration under provider for the whole system. No solution for resellers.
Contact TAM/PTA in order to request a hotfix for the issues.