Aliasing - possible bug?

Hi, interesting behavior I had found and I need some explanation. WL Pro 11.0.20, soundcard UR824, latest ASIO driver (2.0.4), S/R set to 44100. I used the built-in Signal Generator to generate a frequency sweep (16 Hz - 20 kHz with -1dBFS peak, length 10s, 24/44100). As soon as I played it back I registered some artefacts (aliasing) starting from approx 3 kHz and everything was like “radio tuning”. Spectrogram, 3D Frequency Analysis - everything looks like correct clean tone with smoothly frequency change and nothing added. Comparing this with Cubase 11 Pro there is playback correct (i.e. no aliasing heard, clean tone sweeb from low to high frequencies). If I switch to another soundcard (built in) or to Generic Low Latency ASIO driver (which in facts uses the built-in soundcard too) the playback in WaveLab is also correct.
So why there is the big difference when using UR824 with its ASIO driver in WaveLab (wrong sound of the sweep) and in Cubase (correct sound of the sweep)? Due to the relationship with the driver I mentioned I really dunno if this may be reproducable with another soundcard (when using its native ASIO driver) or whether it is related to UR824 only (but then I really duno why the playback in two programs differ even the soundcard`s settings/driver are the same). May it be some WaveLab bug?
Or do I miss something?

Thnx for replies and kind regards!


Link to the video which shows the described behaviour:

Update: everything suddenly disappeared. Dunno why :-/ I may did only a few driver`s change (as I mentioned) and 2-3 times restarting of WL. Strange…

Now it seems to be OK as I expected (=no artefacts in playback of the sweeped signal).

Thnx anyway.