Redis xreadgroup not blocking when timestamp ID is used

XREADGROUP with BLOCK x seems to be ignored when using a timestamp ID and returns immediately

127.0.0.1:6379> XREADGROUP GROUP mygroup bob COUNT 1 BLOCK 0 STREAMS mystream 1585868580914-0

1) 1) "mystream" 2) (empty list or set)

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XREAD, using same values as above works as expected and blocks

127.0.0.1:6379> XREAD COUNT 1 BLOCK 0 STREAMS mystream 1585868580914-0

Comment From: huangzhw

@gittyup2018 Because with XREADGROUP, when you specify an id, this will return entries in PEL, BLOCK is useless. You should specify id >, then it will block.