In a coordinated effort between PowerDNS, ISC, CZ.NIC and NLnetlabs, starting Feb 1 2019, workarounds for severely broken EDNS setups will be removed from our collective body of software.
For the PowerDNS Recursor, this will happen in the 4.2.0 release.
Please read the full article by CZ.NIC, read these slides from ISC, or watch this OARC presentation.