Is this a defective planchet? From the front is doesn't look like it, and it doesn't look like this coin had much opportunity to get damaged like this. This is the edge. The first picture lines up with the mark above CU in Cumhuriyeti. The second picture lines up with YE in Turkiye. Oh, by the way, if you know where this came from, can you tell me?
What is the composition, brass? It could be that the upsetting mill exposed a fissure in the blank or lamination of some sort.