Behavior - Is this normal?

Owl's SW and I were talking earlier about how she interacts with the EI teacher, she's had some behavior issues for awhile during their sessions. The SW brought up that she noticed the longer Owl works with her service providers, the worse her behavior gets with them.  I was talking to DW the other day about the same thing but in regards to her and myself.

I am a SAHM and Owl's worst behaviors arise with me.  She favors my DW and looks to her for fun and to get her out of things she doesn't like to do (sensory play, eating, baths, time outs). It sucks to be the "bad guy" but being the SAHM, I have to do the not fun therapies and discipline.

We've seen Owl go from completely attentive and engaged when first working with a provider to distracted, ignoring, and rude.  Last week, the EI teacher was working on grouping like objects and taping them to paper, Owl kept avoiding/ignoring her, then telling her no and kicking the paper and grouped objects away, then grabbing the tape roll out of her hands and throwing it at her.

This escalating behavior happens with every single provider/therapist we've worked with but it seems to be getting worse as she gets older and has more words.  She is cognitively somewhere around 18 months per the neuropsych so I'm not sure if it's a terrible two's thing or something we need to look into more.

The EI teacher had a BT come out with her two weeks ago to observe and give guidance but because there was a new person here, Owl's behavior was great, the next session (no BT this time) it was back to the behavior problems.

Tell me, is this normal?