Steps to reproduce:

Open the attached project
Run QA > 1. Check Damaged Asset. The project ships two graph assets: pristine.qagraph, and damaged.qagraph which is the same file cut in half, the way an interrupted save or a bad merge would leave it
Read the Console
Run QA > 2. Save The Loaded Graph
Close the Editor, reopen the project, and run QA > 1. Check Damaged Asset again

Actual results: Step 3 prints "VERDICT: FAIL - silent partial load, nodes=2/4 vars=0/3, no error logged". The damaged asset loads as a valid graph with two nodes and all three variables missing, and nothing is logged. The control on the line above loads pristine.qagraph fully, 4 nodes and 3 variables. Step 4 rewrites the damaged file as clean, well-formed YAML, 6373 bytes down to 4709, and step 5 reports the same 2 nodes and 0 variables, so the loss is permanent. StateMachineDatabase.LoadStateMachine is worse: every truncation tested reports success and loses all 4 states.

Expected results: The dropped content is kept as a missing-type placeholder, or the load is refused, or at minimum the file is named in a warning. Graph Toolkit already refuses other damaged files, returning null for a dangling rid, an unknown format version, a negative rid, an unresolved merge conflict, a zero-byte file and for some other truncations of this same asset. Unity's Scene and Prefab importers detect truncation, name the file and report that it might be corrupt. Note this is not the missing-type path working as intended: that path keeps the model in the graph and marks it, and it preserves the broken data on save. Here the models are gone from the graph entirely and saving discards them. AssetDatabase agrees the file is damaged, LoadMainAssetAtPath returns a DefaultAsset and LoadAllAssetsAtPath returns 0 objects, while GraphDatabase.LoadGraph on the same path returns a graph and reports success.

Reproducible with versions: 6000.7.0a6, 6000.7.0b2, 7000.0.0a1

Not reproducible with versions: 6000.6.3f1, 6000.7.0a5

Can't test with versions: 6000.0.84f1, 6000.3.24f1 (com.unity.graphtoolkit does not ship in those streams)

Tested on (OS): macOS 26.6.2 (Darwin 25.6.0), Apple M1 Max