Actually the package mod_md is not able to see the OCSP status of a certificate when nextUpdate field is not set. Directly mod_md rejects the responses when nextUpdate is not set. You can see the specifications in the following RFC:

https://datatracker.ietf.org/doc/html/rfc6960#section-4.2.2.1
If nextUpdate is not set, the responder is indicating that newer
revocation information is available all the time
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For example, the following CA/B Forum Baseline Requirements -specifies the requirements for publicly trusted CAs - require an OCSP response validity period >= 8 hours and <= 10 days.

Instead of mod_md rejecting these responses when nextUpdate is not set,  it should set valid.end to valid.start plus some fixed interval