http doesn't forward to https on Google Chrome - redirect

Question

I have a website: https://www.example.com running on IIS 10 on Windows Server 2016. I have URL forwarding set up so that if somebody goes to the non-www URL, it redirects to the www. If they go to http it redirects to https. In the past this has worked just fine.
Today I get a call that somebody can't get on to the site. Turns out that Google Chrome doesn't redirect http to https -- it comes back with a 403. Every other browser I've tried works fine (including the new MS Edge, which is Chromium-based). Going to https://example.com does successfully redirect to the www.
Here's the redirect, which has worked just fine until (not sure when) recently. I have tried these in either order.
<rules>
<clear />
<rule name="Force www." enabled="true" stopProcessing="false">
<match url="(.*)" />
<conditions logicalGrouping="MatchAll" trackAllCaptures="false">
<add input="{HTTP_HOST}" pattern="^pwaportal\.com$" />
</conditions>
<action type="Redirect" url="https://www.pwaportal.com{REQUEST_URI}" />
</rule>
<rule name="Force SSL (https)" enabled="true" stopProcessing="false">
<match url="(.*)" ignoreCase="false" />
<conditions logicalGrouping="MatchAll" trackAllCaptures="false">
<add input="{HTTPS}" pattern="off" />
</conditions>
<action type="Redirect" url="https://{HTTP_HOST}{REQUEST_URI}" redirectType="Permanent" />
</rule>
...
</rules>
Note: If somebody has successfully pulled up the page in the past, it works fine. Chrome I suppose is caching the final URL, or the fact that it should use https for that domain.
UPDATE: The Plot Thickens: I tried it on Safari. Safari downloaded a 0-byte file called "example.com"