Big air bubbles in pre-filled med syringes for cat - is this is normal?

Our 16 year old cat with dementia/pain gets bupreorphrine (among other meds) at night. Each week we pick up a one week supply of pre-filled syringes that they have to get out of a locked case at the vet, that we then squirt into her mouth.

Our cat has been worse lately, so yesterday the vet advised us to combine the dosages in the syringes for her at night until we can get a refill at a higher dosage, and it's the first time I've looked closely at the liquid in the syringes.

The prescription is for .3ml per night. The stopper of each syringe is at the .3 mark, then there is an air bubble .05 - .1 long, then the actual liquid starts around .2. It's pretty consistent across the syringes.

Is this a normal way to fill these meds or maybe just someone filling them in a hurry, or does this seem like someone diverting meds from each syringe? How common are air bubbles?

Thanks for any input!

Species: Cat Age: 16 Sex/Neuter status: Spayed Breed: Mackerel Tabby Body weight: 10lbs History: Kidney disease, dementia, arthritis, bronchitis