Gerber #21-302 Ultra Flush 1.6 gpf

Recently installed subject toilet. Have noted at flushing that bubble(s) emit from "jet hole" in bottom of bowl. Bubbles may be 2" diam. Have plenty of water pressure, and all items checked out aok with Sloan unit.

I am beginning to believe that some bubble from jet hole may be normal.
Any thoughts or experience with same?

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