Update README.md

README.md

@@ -35,6 +35,15 @@ Note that targets have missing values. Algorithms should be evaluated only on pr
 |  Recommended split |         scaffold         |
 | Recommended metric |       AUPRC, AUROC       |
 
+**Warning:** in newer RDKit vesions, 2 molecules from the original dataset are not read correctly due to disallowed
+hypervalent states of some atoms (see [release notes](https://github.com/rdkit/rdkit/releases/tag/Release_2024_09_1)).
+This version of the PCBA dataset contains manual fixes for those molecules, removing additional hydrogens, e.g. `[AlH3] -> [Al]`.
+In OGB scaffold split, used for benchmarking, both molecules are in the training set. Applied mapping is:
+```
+"CC(=O)O[AlH3]OC(C)=O" -> "CC(=O)O[Al]OC(C)=O"
+"CCCCO[AlH3](OCCCC)OCCCC" -> "CCCCO[Al](OCCCC)OCCCC"
+```
+
 ## References
 <a id="1">[1]</a> 
 Ramsundar, Bharath, et al.