I can see a possible case being made.
"One of the soldiers who ate a cupcake and felt fine collected about five wrappers and gave them to the chain of command — one Warrant Officer Mangrove, according to the court document.
The base military police officer who attended the scene, Cpl. Benjamin Whitehall, obtained one of the wrappers from a soldier who got it from Mangrove and tested it for drugs. The test came back negative but later tested positive for traces of THC, according to both Kasper's court document and the response from military prosecutors.
The military police only discovered other wrappers existed almost a year and a half later, in January 2020, after a request from the accused's lawyer."
Soldier collects "about five" wrappers and gives them to the WO. WO gives one only of the wrappers to another soldier who then gives it to the MP. MPs test the wrapper and it comes back negative. Retest the wrapper and it now comes back positive. None of the other four "or so" wrappers are tested to see if they come back positive or negative. In fact they no longer can be found.
Chain of evidence issues? Initial soldier that collected the wrappers felt fine, but he did eat one of the cupcakes. Where did he collect the rest of the wrappers from? The garbage? Was the garbage can tested in case it had traces of THC from some other source? Why was only one of the "about five" wrappers given to the MPs? How was the one that was turned over selected over the other ones? Why didn't the WO give the wrappers to the MPs himself? Where & how were they stored by the WO? By the individual that turned the one over to the MPs? Why the initial false negative test on the wrapper?
Also, how did it come to light that there were additional wrappers? The WO chose only to turn over one to the MPs and presumably he/she didn't mention that there were additional wrappers. How did the accused's lawyer know that there were originally more than the single wrapper when they raised the issue in January 2020?
None of this of course proves that she didn't feed the troops laced cupcakes. However with the initial negative result on the one wrapper that was handed over it could look like an opportunity was missed to cross reference that test with tests of the other wrappers. It they all came back positive then it would look pretty damning. But we'll never know because they didn't get tested. Now we've just got one piece of evidence that passed through a number of hands before reaching the MPs that at first tested negative then later tested positive. Reasonable doubt?