Temporary Low Voltage Issue in PV String with Huawei 15 KTL Inverter: Unexplained Voltage Drop

Hello everyone. I have a PV array, with two strings, both with 18 panels, one with 16 on south and two on east and one with 12 south and 6 east. On the second string mentioned, in the morning, even if I do not have shade in my area, for a few hours, the voltage decreases around 160 V and the current increases, and on the other one the voltage is normal. I have a Huawei 15 KTL inverter. After a few hours, the strings become equal as voltage. I really didn't discover what can cause this situation. Please give me any advice or solution if you met something similar in your experience. Thanks

Added after 3 [minutes]:

Hej, rozwiązałeś ten problem ze zbyt niskim napięciem na stringach obsługiwanych przez inwerter Huawei? Mam od miesiąca ten sam problem i jakoś nikt nie jest w stanie mi pomóc... A produkcja ucieka....