Google tests mixed blue and black sitelink colors in sponsored ads

Google may be testing a mix of colors for sitelinks in sponsored results. I spotted an ad where the first two sitelinks were blue and the ones below them were black.

Here is a screenshot:

Google has tested sitelinks in all blue and in all black in the past.  This is the first time I’ve seen both colors in the same ad.

I’m not sure whether this is another color experiment or a possible bug. Blue text is commonly associated with clickable links, so it may attract more attention than black text. However, we don’t know whether this color difference has any impact on clicks.