For anyone who stumbles across this post:

I replaced the dimmer with the same model, but different hardware version:

Old - Hardware version 2.0

New - Hardware version 1.8 (in the app it shows up and Hardware version 1)

The Hardware version 1 switch turns on reliably all the time compared to Hardware version 2.  With the version 2, the delay was random and could be anywhere from 0.5 seconds to a full 2 seconds (maybe longer) which feels like an eternity when you're walking into a windowless bathroom at night.  The version 1 dimmer turns on reliably with only a 0.5 second delay all the time.

Not to mention the hardware version 1 physical switch button feels more solid and tactile when you press it compared to the version 2, which felt mushy and squeaked every time i pressed it.  It appears the reason these have droppd in price and are on sale lately with such low prices is that they have a different manufacturing process to cut costs (and thus cut corners).

I have installed 3 version 1 dimmers and all seem to be solid, turn on quick, and feel nice to press.  Of all the version 2 dimmers i got, at least half of them have mushy and squeaky physical buttons.  Not sure if I should continue to replace all my switches or go a different route...

@pchoi94 Where did you find v1.8? I bought mine off Amazon and they are v2. Honestly, I'm very disappointed talking to kasa support so far, they are still completely unaware of this delayed start issue. I've upgraded to firmware 1.0.5, makes no difference. Will a human being on that product team give their own dimmer switch a try already? It's so annoying, I'm thinking about just returning back to Amazon. Not sure if it's intended but the delayed start is either poor design or defective. The old folks in my house can't figure out how to use the switch properly because they get confused by the delayed start! 

@pchoi94 thanks, I guess they're all flawed. I'm so disappointed with how the dimmer switch behaves. I'm even more disappointed that their product team doesn't even let their support team know about this issue. After 2 replies from the support team, they have ceased communication. I own 12 single pole,  2 3-way, and 3 single pole dimmers.  I was anxiously awaiting their new 3-way dimmers and sensor dimmers, but now I'm having second thoughts about owning Kasa in general. 

@pchoi94 I was reading another thread about this an it seems to be a designed that way.  They say the delay is needed to sense if it was a double click feature.  Is the double click feature not available on the older versions?

@KobeT Double click feature is pretty useless 99.9% of the time. While the idea sounds interesting, it is obviously a design flaw for them not allow users to turn off this feature. 

@KobeT I agree that delay is necessary for double click. As a designer, i believe it's a mistake to think all customers will like this gimmicky feature. I actually really like their single pole switches but I'm so disappointed to have a dimmer installed next to a single pole and they work like they're made from 2 different companies. 

@dark9t316 I know I'm 8 months late, but throwing my support here in the hopes this is fixed at some point. We have the same situation. YOu can hit both switches at the exact same time, and the lights turn on/off 2+ seconds apart. It's obnoxious...