MV line stats that a minimum of 3 days (or there abouts) of footage is already held regardless of smart retention being enabled. Anyone else discovered the message "there is no footage" for a period within this minimum retention time frame? because we did and we couldnt playback some footage that was only 2 days old. However when the motion was detected the footage became available. So looks like the smart retention was kicking in as designed by even during the 3 day period.
Please raise a case to make sure something unexpected is not happening. If you have motion based retention enabled it should have all of the last 72 hours (3 days) of video.