[IntelliJ] Uncaught Exception Operator called default onErrorDropped reactor.core.Exceptions$ErrorCallbackNotImplemented: java.util.concurrent.TimeoutException: Did not observe any item or terminal signal within 10000ms in 'subscribeOnCallable' (and no fal

IntelliJ build version: 2026.1.1 IU-261.23567.138
OS: Windows 11
JDK: JetBrains s.r.o. 25.0.2
Plugin version: 3.97.5-2026.1
Additional Info: None
Parent component:

com.intellij.openapi.wm.impl.IdeRootPane[,7,7,1536x816,layout=com.intellij.openapi.wm.impl.IdeRootPane$CustomHeaderRootLayout,alignmentX=0.0,alignmentY=0.0,border=,flags=449,maximumSize=,minimumSize=,preferredSize=]

Error message:

IdeaLoggingEvent[message=Operator called default onErrorDropped, throwable=reactor.core.Exceptions$ErrorCallbackNotImplemented: java.util.concurrent.TimeoutException: Did not observe any item or terminal signal within 10000ms in 'subscribeOnCallable' (and no fallback has been configured)
Caused by: java.util.concurrent.TimeoutException: Did not observe any item or terminal signal within 10000ms in 'subscribeOnCallable' (and no fallback has been configured)

Start by reproducing the reported exception in IntelliJ 2026.1.1 on Windows 11 with plugin version 3.97.5-2026.1. The payload names no source files, tests, or entry points, so trace the Reactor timeout from the reported subscribeOnCallable operation. Done should mean the timeout no longer appears as an uncaught dropped error, with a regression check identified.