user name error on 3.1.0

Trying to create a user name on 3.1.0, and when going to save it, I get an error of 'Configuration could not be saved, seed (sic) details in logs', and the logs show the following Java error

20260521 07:52:27 [qtp1729904998-22453] ERROR com.ubooquity.provider.a.a.a - Failed to read or deserialize configuration from request
com.fasterxml.jackson.databind.JsonMappingException: Unexpected IOException (of type java.nio.file.NoSuchFileException): /tmp/JarClassLoader/kotlin-stdlib-1.8.22.jar.9396437004828442146.tmp
  at com.fasterxml.jackson.databind.JsonMappingException.fromUnexpectedIOE(JsonMappingException.java:346)
  at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3776)
  at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3740)
  at com.ubooquity.f.f.a(SourceFile:52)
  at com.ubooquity.provider.a.a.a.k(SourceFile:297)
  at com.ubooquity.provider.a.a.a.a(SourceFile:80)
  at com.ubooquity.provider.a.a.a.processRequest(SourceFile:71)
  at com.ubooquity.d.a.a(SourceFile:63)
  at com.ubooquity.d.b.handle(SourceFile:54)
  at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:122)
  at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:223)
  at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1381)
  at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:178)
  at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1303)
  at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:129)
  at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:141)
  at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:122)
  at org.eclipse.jetty.server.Server.handle(Server.java:563)
  at org.eclipse.jetty.server.HttpChannel.lambda$handle$0(HttpChannel.java:505)
  at org.eclipse.jetty.server.HttpChannel.dispatch(HttpChannel.java:762)
  at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:497)
  at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:282)
  at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:314)
  at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:100)
  at org.eclipse.jetty.io.SelectableChannelEndPoint$1.run(SelectableChannelEndPoint.java:53)
  at org.eclipse.jetty.util.thread.strategy.AdaptiveExecutionStrategy.runTask(AdaptiveExecutionStrategy.java:416)
  at org.eclipse.jetty.util.thread.strategy.AdaptiveExecutionStrategy.consumeTask(AdaptiveExecutionStrategy.java:385)
  at org.eclipse.jetty.util.thread.strategy.AdaptiveExecutionStrategy.tryProduce(AdaptiveExecutionStrategy.java:272)
  at org.eclipse.jetty.util.thread.strategy.AdaptiveExecutionStrategy.lambda$new$0(AdaptiveExecutionStrategy.java:140)
  at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:411)
  at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:969)
  at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.doRunJob(QueuedThreadPool.java:1194)
  at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:1149)
  at java.base/java.lang.Thread.run(Thread.java:840)

Any way to create a user on an already configured system?