The transcend 32 gb CF cards have trouble in snow leopard in terms of ejecting from the computer. This problem doesn't exist for those who simply drag & drop into the trash/eject. I have 2 such cards and have never had a problem with them. I have never had problems with my transcend 16gb SDHC cards.
I have had recent problems formatting my SDHC sandisk 32gb (class 10) cards with my EX3 however. This is a problem of the camera not being able to reformat the card after I've used it on several occasions. I haven't figured out what that's about yet. It's formatted as fat and still isn't recognized by the camera. Using a kensington 7-1 reader card.
Regarding the formatting of your Extreme SanDisk 32GB class 10, you will find that the Kensington 7-1 adapter may have outlasted its use as it is using an IC controller which was manufactured way before 32GB memory cards were released. So, the chances of this particular controller working with your SDHC, being the latest, is going to be not highly probable... I can't comment in regards to other 32GB memory cards, as I don't know if any Kensington 7-1 adapters are in use with them, off hand.
Every manufacturer of memory cards and every brand of memory cards use different memory IC controllers and firmware, so to get an adapter to recognise a memory card on EX1/EX3 in regards to formatting is a daunting task because there are so many ways that the adapter can be manufactured (in regards to USB 2.0 bus lane choices).
With MxM adapters, I can't speak for any other brands...but the SanDisk Extreme example 32GB class 10 will not do consequetive formatting on EX1/EX3. In order to do consecutive formatting you have to eject the adapter and re-insert it and it will format. Transcend 32GB for example on every 3rd consecutive format with show a media error, where you have to re-insert the adapter with memory card and then you can continue with the formatting.
There is no such issues with 16GB (any brand) at all because they will format consecutively.
Also, formatting behaviour will be slightly different between slot A and B...
Additionally, formatting behaviour and not being able to format at all... there are 2 main reasons for this which are:
(1) the SDHC is not aligned in the adapter socket; and
(2) in the majority of cases, the firmware and IC controller of the memory card is not compatible with EX1/EX3 cameras.
ATP 32GB memory is different in this regards because it will format on EX1/EX3 consecutively in the same way as any 16GB memory card, but only because we used the manufacturer's knowledge to tweak the firmware for the EX1/EX3 camera to be able to do this, regardless which slot (A or B) it is in.
In my view, it sounds like you need a new adapter because the SanDisk Extreme 32GB class 10 is a very good memory card, so upgraded IC controller may solve your problem.