HRR switches between "unavailable" fill and "available" fill based on zoom

[krivard]

Actual Behavior:

FL - Orlando (HRR) appears with the crosshatch fill used for Estimate Unavailable, but switches to the (correct) yellow fill when you zoom in.

Steps to Reproduce the Bug:

1. go to https://dev--cmu-delphi-main.netlify.app/covidcast/?sensor=indicator-combination-confirmed_7dav_incidence_num&level=hrr&date=20201129&signalType=value&encoding=color&mode=overview&signalR=true
2. center the view pane on Florida
3. zoom in and out and watch the fill change

Expected behavior

Shouldn't display as unavailable.

Screenshots

"Unavailable" zoom level:

"Unavailable" fill with values nevertheless in tooltip:

"Available" zoom level:

Rating Scale (1 is minor, 7 is severe): borderline release-blocking? I'm so sorry I didn't poke at this earlier. :(

Context

• Browser: Chrome 87.0.4280.67 on a Mac