33 dB difference!!! Something is broken or wrong here!!! 33 dB is HUGE.
You mention to break the squelch, this may not be a wise test. Also do you have the squelch set consistently at 2 bars on each radio?
Also make sure the 996T does not have the attenuator on.
If the attenuator is not on, at 33 dB difference I would have to guess that the front end or filter matrix has a problem. Most likely caused from a installation where there was too much near field RF energy from a transmitter that damaged something?
Is this just in a specific band or across the board in frequencies?
Also you may want to test with a 1 kHz tone, squelch off to full quieting and see what the difference is between the 2 radios.
I could see maybe a 3-4 dB delta, but 33 dB is not likely a difference in the design but a problem with the radio if the attenuator has not been turned on.
Also compare the radios below 30 MHz, using a Weather channel and in the FM broadcast band. I have seen a lot of the x96 models where there are failures in the filter switching matrix or mixer stages where the radios only work properly in the lower frequency ranges. I did not find the specific switch point, however, I have one radio that will not receive any of the FM broadcast band or above, but seems to be fine in VHF Low Band, it picks up the CB band fine but this is it.
30 dB loss can also be a broken antenna connection. I have seen 30 dB loss when there is no physical/electrical connection on an antenna or feed, so it may be worth checking to make sure the BNC female terminals are not spread due to someone using the wrong center pin or a wire and then maybe open the scanner and check the connection from the BNC connector to the main circuit board. Make sure there is not a cracked or broken solder joint.
Good luck.