I heard back from support. They suggested switching themes, but my site’s custom theme has to be kept online. They also suggested disabling Jetpack, but it hasn’t fixed the problem.
I’m going to try increasing the memory limit again. If it doesn’t work, I’ll just downgrade. Here are the instructions if anyone needs them. Scroll down to Troubleshooting.
https://www.advancedcustomfields.com/resources/upgrade-guide-version-5/
