LE is expected to preserve the evidence without being asked, and the SA may not be permitted to use certain evidence if other evidence is not preserved. However, in this case there are some obvious questions, including (1) was the smell of the garbage "evidence" at all, and (2) is it possible to "preserve" a smell anyway? LE trapped and tested the gasses emitting from the trunk liner, and also trapped and tested the air from the trash bag. LE still has the can containing a piece of the trunk liner, but as JB's motion points out, that can doesn't really "smell like the trunk" at this point--it smells like the gasses that have emitted from that little piece of the trunk liner. So LE really didn't, and couldn't, "preserve" the trunk smell. In which case, why would anyone expect LE to "preserve" the trash bag smell?
JB's motion seems to assume that the SA intended to have the jury smell the can containing the bit of trunk liner as "evidence" of the decomp smell. I personally doubt that was the strategy. I suspect that the evidence of the smell was and is going to be the testimony of Yuri, the tow yard guy, Cindy and George. Similarly, all those same people can testify about the smell of the trash.
The jury would not get to hear testimony from the bond hearing. Just because something was allowed at the bond hearing does not mean it has to be allowed at trial.
IIRC, JB was asking to exclude ALL references to the smell. I assume that includes Yuri's opinion, expert or not.