I built the D4D kit a couple of days ago and it worked well. I didn't make any QSOs just yet, but the band conditions are not good so this isn't a problem.
Yesterday, however, I powered up the transceiver and I noticed some issues. You will see in my screenshot that the received power level is at 54dB. Previously it was at about 23dB, and I was able to receive a lot of FT8 transmissions.
Secondly, you will see that the transmission times start one second later than they are supposed to. Previously they were transmitting at :00, :15, etc. without any problems. This happens in both versions 2.0 and 2.1 of WSJT-X. I also noticed that the transmission duration seems shorter than it previously was, maybe lasting about 11 seconds.
Both of these problems began yesterday. At one point I turned on the power to the transceiver and it did not power up: neither the RX or TX lights went on. After a couple of attempts, the device powered up. Occassionally, WSJT-X throws an error about input audio not being found.
Has anyone else every had any of these problems, or know how I might be able to troubleshoot?