How to patch a leak in an air mattress<br>Know that all air mattresses lose air naturally. Before you decide to strip the covers off of you mattress and search for holes, know that no air mattress holds air indefinitely. You will naturally have to re-inflate your mattress whether or not you have a leak.
Air mattresses leak naturally, even if there isn't a physical tear.
The context states that air mattresses can't hold hair indefinitely, suggesting that even if there isn't a physical tear they will still leak the air out, so the statement is correct. The system might have tripped over the use of the word "naturally" because it's a strange word to use about a product but it still fits the sentence.
( z1 leak :ARG1 ( z2 mattress :mod ( z3 air ) ) :ARG1-of ( z4 natural ) :concession ( z5 even-if :op ( z6 tear :polarity - :mod ( z7 physical ) ) ) )