As of the 1.2 update, when out of water guardians cannot make flopping noises anymore. The flopping makes me laugh as it jumps everywhere on the map, but the sounds must be restored immediately. Thanks.
For reference the guardian flop sound in Minecraft Java Edition
And a comparison in Minecraft (bedrock)
Confirmed for 1.2.3.6 (and 1.2.9) on Windows 10.