Hi,
As per second paragraph of Andre Frantzke's reply dated Sep 14, 2018 8:16 AM; we had to check current consumption on VUSB pin. To perform the same, we cut some tracks and tried to measure current but instead we found something else which was matching with second paragraph of Dietmar Walther's response dated Sep 14, 2018 10:57 AM.
In addition, we can also mention in response that we have also tried to decrease capacitance on DVCC pin as per their suggestion, but the result was same. This again makes us to believe that the issue is only because of humidity.
Request you to please do the needful