Recipes and images might and will contain sigdata that change from one run to the next, deliberately or inadvertently. Unless taken proper care of the result is very often a "taskhash mismatch" error. However, the root cause for taskhash mismatch errors is often extremely difficult to find. My personal experience is that workdays have been lost due to them.

On a general level, bitbake is missing methods for efficiently identifying "taskhash mismatch" errors. The root cause might be poorly or wrongly written recipes, but the tools should be able to highlight where the failure is originating from.