I had a similar experience with pure Sn and In targets. Both have a low melting point around 240°C for Sn and 160°C for In, thus if you use too much power (either DC or RF) you can heat the material up past to its melting point, that is why your target has a copper backplate, it should help you dissipate heat.

In your case, the target still looks to be useable but i would check just in case if the stoichiometry is corrected as it looks like indium has escaped to the side.