Some submissions not showing in database (ID Jump , not spam, not other form)

I recently add reservation form with paypal on my website, all the configuration is good , paypal work nicely but i encounter an issue.

My paypal account get some payment i couldnt linked with form submission , so i look into the database and saw that they were some ID missing (ex: jump from ID457 to ID461). I search for a solution on forums and see that could be spam, so i check on my phpmyadmin wp_frmt_form_entry and see this :

https://ibb.co/CWwW221

so all of my submission exist in the db and arn’t spam (is_spam=0 everywhere)

so i decided to take a look at my wp_frmt_form_entry_meta to see those who are missing and see that :

https://ibb.co/19Gtsxv

you can see form ID jump from 457 to 461, i have the same result in my submission panel on WordPress plug in.

The strangest thing is that user who filled these “missing” forms payed with paypal and the payment is correctly made in my account. I also see that could be an other form that made ID jump like this because they all connected to the same ID list but no … i only have 1 form active on my website.

It occured on different timing of the day ( i also checked wp cron to see if they was any conflict) and not on all submission , some of them with paypal payment are correctly showing on database.

I just don’t understand how can this be possible, It’s as if after the payment is made through PayPal, the user is not properly redirected to the form page and consequently, the information is not sent to the database.

Thank you for your consideration, i hope explanation wasnt too long and boring ??