I get the same as both nerdymama and alfonso, however for me what seems to cause it is either mental tiredness, being overwhelmed or too many distractors causing different sources of information to merge into one. I also have other variants of this, for example it can be difficult for me to use words myself - like attatch words to my thoughts.
Not much you can do, for me I have improved this by trying to prevent myself from getting to tired/overwhelmed (e.g. spending more time in quiet places), and meditiation activities as well as other tricks to filter information sources better and ignore distractors.
Now you know what causes the problem perhaps try to find ways to compensate or reduce the problem. For the first hour could you work in a different room or put up a partition around where you work, could you change your work hours to start one hour later and finish one hour later.
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