Mostly when I begin to dictate after the first word I get a failure message as "index and length of the string must be in the same position. Parameter: length

Hi I use Trados 2017 and Dragon. Mostly when I begin to dictate after the first word in a field I get a failure message as "index and length of the string must be in the same position. Parameter: length (might be similar because the message is in German). When I close the message I can continue but have to remove one of two insert spaces. Sounds like not a big issue but if you do it files with 1000 or more fields it is annoying and delays work. It happens only in Trados 2017 where the first letter of the first word in a field changes automatically upper letter. In earlier versions that failure did not appear. I always hope that bug will be fixed with the next update but without any result.