Surging in All-Sky LAP TPW

We've seen a couple of cases where the All-Sky LAP TPW surges back and forth unrealistically over a half hour intervals.  Here are three frames 1/2 hour apart from 1458 / 1528 / 1557 UTC 8 May 2019.  Note the surging TPW over the eastern OK / northwest AR region.

1458 UTC


1528 UTC


1557 UTC


1458 UTC Data type (yellow / gray cloudy)


The data type indicates this is in a cloudy region.  What's odd is the middle frame is different, then the last frame is more like the first.  Perhaps this is related to handling of the new 12 UTC GFS cycle?

JohnF