I had disabled SBS SD a while back.
There used to be a minor difference between the HD and SD channel during the A-League (I think).
The A-League was on SD and some other non-sport show was on HD.
Not sure if that is the case anymore, so I disabled SD.
I remember that, from last year. I was surprised that SBS decided to slightly change their program lineup for an international soccer series and not stick to simulcasting SBS and SBS HD. They may do it again for the World Cup (if they have the telecast rights next time it's on).
What does the Toppy do regarding guide data?
Does it first fetch 5 days of guide data once-only (assuming you don't wipe the EPG data with a reset), then re-check daily?
If the toppy has no guide data (after a EPG reset or factory reset or clearing the channels) the toppy will fetch the full 7 days EPG for all channels at once. I'm sure after that it would only be fetching updates to the existing 7 days and data for the rolling 7th day.
Some people disable a few channels, let the toppy load the guide and then re-enable those disabled channels. The problem with that is that lately each Wednesday seems to have enough extra guide data to trip up the toppy again. For ongoing reliability you are better off disabling 2 or 3 channels and leaving them disabled.
Here is hoping the disabled 9 & 10 SDa channels fixes my issue.
If 9 and 10 aren't enough you could disable 1 more channel. One that you don't watch. Maybe the Food Network or NITV or the Community Channel if you get a community channel.