Checksum validation failed when downloading org.openhab.transform.exec-3.3.0.jar

Coming from OH 2.5 I did a fresh install of OH 3.3.0 using the official Docker image and added a few bindings and transformation (using addons.cfg). One of these transformations generates an error:

[WARN ] [her.internal.impl.WarnChecksumPolicy] - Could not validate integrity of download from Checksum validation failed, no checksums available

Can this be ignored?