The liability question is feedback. The issue that I repeatedly highlight in these discussions is that the syllabus does not properly reflect the question bank, or vice versa, and therefore some element of feedback is essential. In this case the LO is
010 01 02 05 Explain the Conventions and Protocols designed to cover liability towards persons and goods in accordance with the Warsaw System based on the Convention for the Unification of Certain Rules Relating to International Carriage by Air, Warsaw, 2 October 1929.
...and the 2 year limitation is in Article 29 of the Warsaw Convention. But without the feedback who would know that EASA require you to remember this? Are the candidates expected to remember all 41 Articles? A proper LO would be "State within which time period a claim under the Warsaw Convention must be brought?".
PS The airbus IRS does compute sideslip, for example google A310 Flight Instruments, FCOM pages 10, 16 &17, side-slip index (and beta target). With due respect to your theory provider they should know this, and that the 2 year time limit has been asked.