I have a form with 7 lookup rules, a couple that grab data based on the current form user, and a couple that fill tables based on that data.

Initially, I had the tables fill automatically and it seemed to work fine, but after a couple weeks of use, I began getting the following error when I attempted to submit the form, about half the time.
 

vendor.js:74 ERROR Error: Uncaught (in promise): TypeError: Cannot read properties of undefined (reading 'split')
TypeError: Cannot read properties of undefined (reading 'split')
    at Na.getHiddenFieldIds (main.js:1:796095)
    at Na.processFieldForSubmission (main.js:1:795130)
    at Na.getSubmissionData (main.js:1:793317)
    at main.js:1:807519
    at Generator.next (<anonymous>)
    at d (vendor.js:148:1721)
    at B (vendor.js:148:1923)
    at B.invoke (polyfills.js:6:7338)
    at Object.onInvoke (vendor.js:74:58153)
    at B.invoke (polyfills.js:6:7277)
    at Na.getHiddenFieldIds (main.js:1:796095)
    at Na.processFieldForSubmission (main.js:1:795130)
    at Na.getSubmissionData (main.js:1:793317)
    at main.js:1:807519
    at Generator.next (<anonymous>)
    at d (vendor.js:148:1721)
    at B (vendor.js:148:1923)
    at B.invoke (polyfills.js:6:7338)
    at Object.onInvoke (vendor.js:74:58153)
    at B.invoke (polyfills.js:6:7277)
    at $e (polyfills.js:6:18151)
    at polyfills.js:6:17194
    at polyfills.js:6:17301
    at d (vendor.js:148:1756)
    at B (vendor.js:148:1923)
    at B.invoke (polyfills.js:6:7338)
    at Object.onInvoke (vendor.js:74:58153)
    at B.invoke (polyfills.js:6:7277)
    at B.run (polyfills.js:6:2324)
    at polyfills.js:6:18797

I managed to fix it (so far, fingers crossed) by turning on the Auto Fill button for each of the table fill rules.

Does anyone know what the specific source of this type of error is?

My guess is something to do with the order the lookups complete or attempt to write to the page in, since at the beginning it worked fine while were bringing in nearly empty tables and now we have more data.

Hoping to learn what kind of form logic flow I should be avoiding in the future!