Y1 axis labels disappear when Y2 axis is added

When I use both Y1 and Y2 in a plot, the labels on Y1 disappear (screenshot 3). Y1 has numerical values, Y2 has categorical values. Even if I revert to plotting only the numerical values, the labels on Y1 do not reappear (screenshot 4). I tried having only numerical series on both Y1 and Y2 - same problem (screenshot 5).

ask on Y1

ask and bid on Y1

ask and bid on Y1, rateStatus on Y2

removed rateStatus from Y2

ask on Y1, bid on Y2