It is difficult to determine the liquid level in the circulating hydrogen desulfurization tower

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Since the temperature dropped on the 20th, the liquid level in the circulating hydrogen desulfurization tower of my hydrotreating unit has been inaccurate. The specific issues are as follows: 1. There is liquid present in both the upper and lower float-type level gauges (the liquid phase tube of the upper gauge is located below the gas phase tube of the lower gauge, with the two gauges overlapping by about 30 cm). When flushing these two level gauges, both gas and liquid phases are present; the liquid level in the lower gauge does not reach the level of the liquid phase tube in the upper gauge, but there is liquid in the liquid phase tube of the upper gauge, with little change in that level. 2. There are two types of level remote transmission: float-type and differential pressure-type. The two methods are essentially corresponding to each other, but the changes occur slowly. 3. When the liquid level is slightly high, severe liquid carryover occurs in the recycled hydrogen after separation. 4. Due to the temperature drop, the desulfurization temperature was reduced from 50°C to 40°C; the discharge valve of the desulfurization tower was not functional, so the process was temporarily routed via the bypass line. Is it caused by the entrainment of mist? How should it be dealt with? I would appreciate your advice; thank you!