Issue JDK-8088198, where an exception would be thrown when trying to capture a snapshot whose final dimensions would be larger than the running platform's maximum supported texture size, was addressed in openjfx14.
The fix, based around the idea of capturing as many tiles of the maximum possible size and re-compositing the final snapshot out of these, is currently only attempted after the original, non-tiled, strategy has already failed.
This was decided to avoid any risk of regressions, either in terms of performances and correctness, while still offering some relief to the original issue. 

This follow-on issue aims to propose a fix to the original issue, that is able to correctly decide on the best snapshot strategy (tiled or not) to adopt before applying it and ensure best performances possible when tiling is necessary while still introducing no regressions compared to the original solution.