This could happen typically in two situations.
Situation 1:
In some situation it is possible that you modify your position directly in your portfolio without the suggestion from The Stock Butler.
For example, it is possible that you want to manually raise your protective stop to take profit.
Situation 2:
Another situation where you can see this message is if your protective stop was reached today. In some situation, when the protective stop value is reached, but your position was not yet filled, you will get this message.
For example, the stock starts the day below your buy price, go below your protective stop and then go back up to reach your buy price and stay above your protective stop.
In these situations The Stock Butler knows that you have modified your position, but don't know what field was modified. Therefore, it will show you a message like this:
We could not detect if your position was sold today or tomorrow
You can simply ignore this message since your position was not sold today (more probably tomorrow).
You can also modify your protective stop to be lower than the low of the day instead of the close of the day. This will hide the message, since The Stock Butler will not think that you have reached your Protective Stop.