Anh,
Do you mean to wait 1-2 seconds and reload the page? If so results are the same. They are not simply saved into the database. This is what is get posted to the WP:
gu_field_faq[0][question]: Question 1
gu_field_faq[0][answer]: Answer 1
gu_field_faq[1][question]: Question 2
gu_field_faq[1][answer]: Answer 2
gu_field_faq[2][question]: Question 3
gu_field_faq[2][answer]: Answer 3
gu_field_faq[3][question]: Q4
gu_field_faq[3][answer]:
As you can see, last answer is empty. If I switch to the Classic editor this issue does not happen. So it looks like MetaBox does not play nicely with the Gutenberg.
Is following article still accurate?
https://metabox.io/meta-box-is-compatible-with-gutenberg/
Also this may be relevant too:
https://github.com/WordPress/gutenberg/issues/5718
Any suggestions what to do?