After JDK-8262186, the method is called only once with multiple keyTypes. This means that if an entry is a perfect match (CheckResult.OK) but the keyType for it is not the 1st one, it will be returned along with other possibly non-perfect ones. Thus we cannot only look at the 1st result to determine if there's perfect match inside. See https://github.com/openjdk/jdk/blob/3d657eb0a626e33995af5d5ddf12b26d06317962/src/java.base/share/classes/sun/security/ssl/X509KeyManagerImpl.java#L385.
That said, this is not a fatal error. After all the results are collected they are sorted by matching status and keyIndex, and the perfect match will be picked up anyway.