Creating HashSet in Scala fails with compilation exception

[jankotek]

   val db = DBMaker.memoryDB().make()
    val create3: HTreeMap.KeySet[String] = db.hashSet("bb",Serializer.STRING).create()

fails with

Error:(65, 85) type mismatch;
 found   : org.mapdb.org.mapdb.[String]
 required: org.mapdb.HTreeMap.KeySet[String]
    val create3: HTreeMap.KeySet[String] = db.hashSet("bb",Serializer.STRING).create()

[shuttie]

On mapdb 3.0.8, scala 2.12.11 and jdk11 the issue is not reproducible anymore.