ADV7262 flow back current from Sink

Dear Sir,

We use ADV7262 on our system.

ADV7262's TMDS lines are connected to the sink which have pull up resistors to 3.3V.
In this case, sometimes "1.8V power line of ADV7262" is flow back current from Sink.
Therefore our system effect 1.8V line for other LSI.

Does ADV7626 of TX have "the inflow prevention circuit"(reverce current prevention circuit) internally?

if yes, maybe our system sometimes does't work this circuit.
Please advice us this phenomenon and any countermeasure.

Thanks and Best regard,