Hiding sequences at bottom of alignment can lead to sequence reordering

Open an alignment and hide the bottom 3 sequences. The sequences are hidden and a blue marker is positioned at the bottom of the alignment as expected. Moving up the alignment, leave 2 sequences visible, and hide the next 3 sequences. The expected result is a second blue marker 2 sequences above the bottom blue marker, but instead, there is only one blue marker, 2 sequences from the bottom of the alignment. Revealing the sequences at the marker shows all 6 sequences that were hidden, but now they are above the 2 sequences which were originally in between the 2 sets of hidden sequences.

Possibly related to JAL-2133, JAL-2134, JAL-2265