Registrant change fails on staging

[vohmar]

Replicated on staging with multiple branches including current master. Was not able to replicate it in test nor prod environments

registrant change request results in failure with code 2400 and empty message

errbit:
undefined method `delete' for nil:NilClass
https://errbit.internet.ee/apps/5bcf4873d9d1af60e9179203/problems/60e56e83d9d1af0c46777811

sample request:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<epp xmlns="https://epp.tld.ee/schema/epp-ee-1.0.xsd">
  <command>
    <update>
      <domain:update xmlns:domain="https://epp.tld.ee/schema/domain-ee-1.1.xsd">
        <domain:name>example.ee</domain:name>
        <domain:chg>
          <domain:registrant verified="yes">REG1:5FB74F66</domain:registrant>
        </domain:chg>
      </domain:update>
    </update>
    <extension>
      <secDNS:update xmlns:secDNS="urn:ietf:params:xml:ns:secDNS-1.1"/>
      <eis:extdata xmlns:eis="https://epp.tld.ee/schema/eis-1.0.xsd"/>
    </extension>
    <clTRID>Märi Änn R1-1625648771</clTRID>
  </command>
</epp>

sample response:

<?xml version="1.0" encoding="UTF-8"?>
<epp xmlns="https://epp.tld.ee/schema/epp-ee-1.0.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="lib/schemas/epp-ee-1.0.xsd">
  <response>
    <result code="2400">
      <msg lang="en"/>
    </result>
    <trID>
      <clTRID>Märi Änn R1-1625648771</clTRID>
      <svTRID>ccReg-8765431563</svTRID>
    </trID>
  </response>
</epp>

ui view in registrant portal: