To me the liquid reciever has to maintain a liquid level at all times , otherwise economizer will suffer as well .

ie flash gas and system inefficiency .

As Gary has mentioned non condensibles are of concern as well as condensor efficiency .
It could also be the rock filter drier banking up liquid in condensor . Is there a bypass or has anyone changed them + cleaned filter if it has one ?
Normally filters are on liquid line from liquid reciever to economizer .

Have had instances also if liquid reciever has loss of liquid seal that discharge pressure can go through the roof probably due to to much velocity for refrigerant passing through condensor to change state ( condense ) .

You may also have to investigate higher than normal levels in economizer and low temp accumulator as this is an area also that will be storing excess refrigerant that should be in liquid reciever .
Can you shut liquid makeup from reciever to economizer with stop valve and see what happens to levels and pressures .

What type of level control system is installed on economizer + low temp accumulator ?