Hi Richard,
You do seem to be a bit unlucky. On the first issue it does seem like there is a problem with one of the gates (or possibly a gateline) at that entrance. Do you habitually use the same gate? I’d be interested to see your journey history for the days in question. I’m aware of a couple of instances of gate clocks being out, both at London Bridge NR. On one occasion the time was correct but the date hadn’t changed on an exit gate meaning people touched out the day before they touched in. On the other one the time was about 5 minutes slow and someone was charged peak instead of off-peak. When confronted with evidence I did manage to get TfL to credit the difference for that customer.
The second issue is way more serious. Does your account show just the one set of touches, both in journey history and payment history? Have TfL resolved the issue quickly? If it’s two identical charges at the same time then I’d be inclined to ask your bank whether they can see anything wrong at their end. If you can let me know exact details of when this happened I’ll ask some questions.