Green artefacts on Decklink Mini Recorder HD

Hi, I built a streaming rig with 2 DeckLink Mini Recorder HD PCIe cards. On one of them I get strange green artefacts (see attached picture of both cards shown in OBS). The issue is not in the source signal: if I swap the inputs, the problem remains on this single card.

Is this a hardware problem (defective card), or should I look at other things first? The card and PC are brand new, so exchanging should not be a problem, just wanted to check if this is a common issue and/or has a known fix.