Surprised nobody has answered.
No concerns, as long as you are conducting your high gravity wort production and fermentation well and diluting your higher gravity beer under sanitary conditions with distilled and boiled water.
The mega brewers do this for most of their beers for efficient use of equipment and make it work.
There are many threads on HBT about producing high gravity beers, biggest mistakes people make seem to be under pitching yeast, no oxygenation, and not enough nutrients, aside from all the usual mistakes. Also, expect fermentation to take longer, particularly for clean up after initial fermentation is complete.
