KBAYBO SHOWER FAIL ERROR E3

This electronic shower worked well for almost a year, unfortunately it began to present a problem with the temperature value, the counter indicates a higher temperature than the real one. In the video, with the help of TESTER with a temperature gauge connected to the water outlet, check that the high temperature protection circuit acts when the internal sensor indicates that it exceeds 55 degrees Celsius, however the reading is wrong.
I have contacted KBAYBO China, where the product was purchased by ALIEXPRESS, unfortunately they did not respond at all...