One of the problems in the parent is due to different size calculation between client and server when HFilev3 is used.
Since tags are never shipped to the client in a scan, we can have special size function (or a flag on the current one) that does not include the tags and the tags meta information (the length is what causes the issue), so that client and server will always calculate the same size.
I'll make a patch within the hour, unless somebody beats me to it.
- is superceded by
HBASE-13262 ResultScanner doesn't return all rows in Scan