In the end in our realm (hosted by the Xbox One player) we have placed many water source blocks but even after blocking them off some continue to remain without source blocks floating in the void.

Steps to Reproduce

1? Defeat Ender Dragon

2 Place Bucket of Water in End, that can reach the void 

3 Remove Water Source

4 Spend Time in End, i.e on main island and at varying Y levels such as Y:1 (location of commonly visited Enderman farm)

Observed Results

Varying Heights of Pillars of water remain after source block is removed

Expected Results

Water should completely disappear

If pics do not appear: https://imgur.com/a/biE3Pbz

Noticed water streams remained after creating Enderman farm, and some remained after finishing the farms as well. Have not yet attempted to block off the water entirely. Affecting gameplay by being more inconvenient and in the way.