“Username already registered” on form submission

Hi, thank you for providing such a great plugin

I have an odd issue: On submission I get the error: “This username is already registered”.
– No data is stored, unless I use the “save so far” functionality
– This is a multipage form, it is not a registration form

I’ve tried to
– tune down, then disable Litespeed cache plugin
– followed your steps here: https://wordpress.org/support/topic/failure-when-submitting-form/ – including: 1) uploading your fix to wp-content/mu-plugins: https://gist.github.com/wpmudev-sls/d1e1b64e21fa4cce14921cedd892f811 – and 2) adding “.forminator-custom-form” to TranslatePress settings > Advanced > “Exclude selectors from translation”
– disable Translatepress plugin
– deleted cache (browser cache and Beaverbuilder cache) + performed every new test in new private window,
…but the issue persists.

Please advice
Thank you

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