I can’t figure out why it’s doing this

Hello

Those warnings come from your theme:
/wp-content/themes/fifty50/inc/template-tags.php (lines 498 and 502)
The “fifty50” theme is trying to read data that isn’t there. Best to ask the theme author about it.

A quick fix to hide the warnings: set WP_DEBUG_DISPLAY to false in your wp-config.php. They won’t show on the page anymore – https://developer.wordpress.org/advanced-administration/debug/debug-wordpress/#example-wp-config-php-for-debugging

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Best Regards
Andrei S.