Ive just recently built 5 rigs with the AW-HS50 in it (assuming the E is the european verson?)
Based off what I know about the non E version, at 1080i the switcher will only accept 2 refresh rates 50, and 59.94. (The entire switchers mode can only be set to one or the other).
Looking at the spec sheet you provided a link to, i couldnt find what the refresh rate of your camera shoots at, but with a little googling, I believe it shoots at 60.
So your inputing 1080i/60 and your switcher probably wants 1080i/59.94. It's frustrating, i know. You think why can't the switcher be a little forgiving and accept 60.... well thats one reason they were probably able to price it so low.
FYI the blackmagic Analog to SDI (and most BM Mini Converters) are pass throughs. meaning they dont convert your refresh rate. what you put in is what you get out.