This is amazing, if true.
Consider: under the PRC's "One China" policy, there is only one sovereign authority over all of "Greater China" (PRC, Taiwan, Hong Kong, Macau, etc). As Taiwan is the successor government to the original issuer of the bonds, and China lays claim to that territory, I'm guessing a strong claim could be made that they could be held liable for that debt on the international bond market if the US wanted to force the issue.
Fascinating. Whomever dug this up is to be commended.