Has anyone else had issues with this?
This is how the new UI defines 'Auto Max CPC':
Content bids
You can set a separate cost-per-click (CPC) bid for ad clicks on content network sites. The higher your content bid is, the more likely your ad is to appear on the content network. If you leave this field blank, you'll see Auto appear by default. This setting uses an average of all your ad group's CPC bids.
If you're having trouble deciding on a content bid, use your ad group performance on the content network as a guide. You can set up conversion tracking or Google Analytics to measure performance and set your bids accordingly.
Learn about the lowest content bid you can use for your ads to show on the content network.
Learn more about content bids in general.
Thanks!