Updating the information from comments here for broader community.
@Zein Currently this is a known limitation, failure anomalies alerts do not trigger action groups when they are resolved. Our team is planning to fix this in a coming releases , unfortunately we don't have an ETA yet.
Will keep customers updated as we get more clarity on the ETA.
Thank you for reaching out, hope this answers your query. Feel free to revert back if you have any further queries