Every time the roblox client restarts (i.e. joining another game) this setting reverts to off, which is extremely bad. Settings should NOT be changing without the users choice.
This has been a problem for many months, perhaps even since the feature was added.
This setting is the only way to know if a message has been automatically translated or not, and without it there is no way to give users the benefit of the doubt for innapropriate or rude translations of their message. This itself should also be fixed imo, as it is innapropriate to display processed messages as being from a user without explicitly stating its been processed in any way, i.e. the button to show original message indicates a message has been automatically translated to my primary language.