Hello Jose Gonzalez Gongora,
Welcome to the MS Q&A platform.
To avoid this issue, please configure the retention policy for the delta logs to be less than 31 days. You can also use the immediatePurgeDataOn30Days parameter to trigger an immediate purge of older data.
Reference document: https://learn.microsoft.com/en-us/azure/azure-monitor/logs/data-retention-archive?tabs=portal-1%2Cportal-2
I hope this helps. Please let us know if you have any further questions.