What is the application and did you notice similar behavior outside of it, e.g. being able to paste the currently selected text? I would also check your clipboard manager’s configuration. Clipboards (usually) have a clipboard buffer (for CTRL + C -> CTRL + V) and a primary buffer (for selected text -> mouse middle button paste). Some problems arise from the confusing default settings of some clipboard managers, e.g. the synchronization of both buffers.

An arch user with large arms and spiky hands opens the curtains to look at the dangerous world outside through the window. Perhaps red is indeed a better choice.