I-94 not collected during exit -- Will there be a problem for future visit?

[mythili]

When my parents left the US a year ago, the immigration officer at SFO airport forgot to take their I94 from passport.
My parents noticed this only after reaching India.

They are planning to visit again soon and wondering whether there will be any problem at port of entry because of this?
(Will it look like they have been staying illegaly in the US since the BCIS never received their I94 copy when they left the country)
Thanks for any inputs.

[immihelp]

read https://www.immihelp.com/form-i-94/

[mythili]

Thank you, I will follow that.