Full protection and security, or similar
Arbitrary, unreasonable and/or discriminatory measures
Umbrella clause
Indirect expropriation
https://globalarbitrationreview.com/panama-hit-second-treaty-claim-over-canal-project (requires subscription)
https://www.iareporter.com/articles/panama-round-up-one-new-claim-two-new-tribunals-and-three-arbitrations-about-to-conclude/ (requires subscription)