Okay... this is the same error that we encountered before... onto research!
Let's export the database from RHEL 6 again:
I ignored that warning before... but let's see if addressing the max_input_vars config solves the import issue on RHEL7?
Let's find where the php.ini file is located:
php -i | grep "Loaded Configuration File"
vim php.ini
It's commented; let's uncomment it and then give apache a boot: