The Minerals, Metals & Materials Society: "The temperature limitation for titanium alloys, other than specialized engine alloys, is about 540°C. Above this temperature oxygen contamination becomes an issue, embrittling the surface."
If that frame's been hot enough to melt the Alu components (660+°C) and possibly distort the rear end, all the Ti is suspect. It's all been well into the danger zone for an unknown length of time in an uncontrolled atmosphere with loads of hydrocarbons from the grease and plastic around, then cooled very slowly, again in an uncontrolled atmosphere.