The DVB draft specification for AV1 mentions that:

• payload_unit_start_indicator shall be set to 1
• adaptation_field_control bits shall be set to "11"
• The random_access_indicator shall be set to 1 when the PES packet contains an AV1 KeyFrame
• The elementary_stream_priority_indicator and intra frame interact

It's unclear why these statements are not in the AV1-MPEG-2 TS specification. Could these be different outside of DVB environments?
In any cases, the specification should talk about these fields: either to mandate the behavior or to indicate that the behavior can vary depending on application environments.