I just tried this with Joomla 3.9.19 on PHP 7.3 and do not get any issues. If someone has php7.4 it might be worth trying just to see if they can replicate the issue

I can't reproduce this issue on PHP 7.4.0 and 7.4.6.

@humblehumanbeing is this on a clean installation or do you have any extensions installed?

Ran into this exact issue yesterday with a cron failing. A recent update to SP Page Builder seemed to be the cause for me after I disabled all plugins and indexer worked fine again. Disabling that plugin before indexing, then re-enabling the plugin, solved my issue, and it's a known issue at Joomshaper - may or may not be relevant to you, but I guess it could be caused by a multitude of plugins.

Closing as not a core issue, see https://www.joomshaper.com/forums/smart-search-sp-page-builder-error-0-call-to-a-member-function-gettag-on-null.

But thanks for reporting, @grantg182 . It could have been a core issue at a first look, and better reporting one time too much than one time too little.