In short if the UAS is detectable near terra firma,land asap.You have radio altimeter up to 2500',you have IVSI,you have IRS GS,you know your attitude/thrust settings for S&L and approach.Never attempt to engage automation as it is fed with the same false data.Stay in the circuit,NO CHECKLIST,fly the plane,ignore ALL warnings except EGPWS and land.
If its "single side" anomaly,you cross check the ASIs and hand over control to the pilot with the good data.You still return but now you have more time to play with,checklists may be done etc.
This is wrong and very poor advice on many, many levels.
You started well by saying this can be an extremely confusing scenario. Which is exactly why you would not react according to the quoted part of your post above.
Boeing has a very good Airspeed Unreliable checklist, which will save your aircraft if you follow it properly. It takes time, and with fuel available you should use that time to understand what is wrong with your aircraft, and how to get it safely back to terra firma.
The first (memory) part of the checklist gives you an attitude and thrust that
will keep your aircraft safe.
The rest of the checklist troubleshoots the problem, identifies an accurate airspeed if there is one, and if there isn’t one, gives you attitudes and thrust to get down.
Do LionAir pilots have good training in this area? I have no idea. I am fortunate to fly for an airline that does, and is practiced every 6 months in the simulator.