We ran into an unexpected issue after deployment to production where we started seeing the error:-

Could not parse the filter query: unbalanced `&&` operands.

This issue does not show up in the dev environment with the same exact query and setup, except that dev environment has Typesense 27 and prod has Typesense 26. How can we debug this?

I recommend having the same environment on both dev and production. Also please upgrade to latest v29 since these versions are pretty old.

It seems our problem was related to empty array filter which was fixed in 27