I also get the same results. If I bin my guide camera 1x1 (ASI290mm mini) it usually takes a few seconds after receiving the image and issuing the guide pulse and taking the next image. Binning 2x2 does speed things up, but still takes at least a second.
I do find this to be a bit weird, since on the autofocus tab, with full field enabled, it takes a couple seconds to find all the stars when binning 1x1 on my ASI1600mm Pro. If I bin 2x2 or especially 4x4, it's extremely fast. So I would expect the guiding tab to find the stars pretty fast, since it is lower resolution than my imaging camera.