You are correct. I just tried to initialize a completely fresh Gerrit 3.13 on Windows and it failed with basically the same message.
C:\Gerrit313Test>"%JDK21_LTS%\bin\java" -jar gerrit-3.13.1.war init --batch
[2026-01-15 14:15:25,677] [main] INFO com.google.gerrit.server.config.GerritServerConfigProvider : No C:\Gerrit313Test\.\etc\gerrit.config; assuming defaults
Auto-configured "receive.autogc = false" to disable auto-gc after git-receive-pack.
Generating SSH host key ... rsa... ed25519... ecdsa 256... ecdsa 384... ecdsa 521... done
Initialized C:\Gerrit313Test
Jan. 15, 2026 2:15:28 PM org.apache.lucene.internal.vectorization.VectorizationProvider lookup
WARNUNG: Java vector incubator module is not readable. For optimal vector performance, pass '--add-modules jdk.incubator.vector' to enable Vector API.
Reindexed 0 documents in accounts index in 0,0s (0,0/s)
Index accounts in version 15 is ready
Reindexing groups: 100% (3/3)
Reindexed 3 documents in groups index in 0,2s (15,1/s)
Index groups in version 12 is ready
Reindexing changes: Slicing projects: 100% (2/2), done
Reindexed 0 documents in changes index in 0,0s (0,0/s)
Index changes in version 87 is ready
Reindexing projects: 100% (2/2)
Reindexed 2 documents in projects index in 0,0s (55,6/s)
Index projects in version 10 is ready
ERROR com.google.gerrit.server.cache.h2.H2CacheImpl : Cannot shutdown cache jdbc:h2:file:///C:/Gerrit313Test/cache/accounts-v2;DB_CLOSE_DELAY=-1
org.h2.jdbc.JdbcSQLNonTransientException: Allgemeiner Fehler: "java.nio.file.InvalidPathException: Illegal character [:] in path at index 4: ///C:/Gerrit313Test/cache/accounts-v2"
General error: "java.nio.file.InvalidPathException: Illegal character [:] in path at index 4: ///C:/Gerrit313Test/cache/accounts-v2" [50000-240]
The same with version
3.12.3 worked without issues on Windows.