Pretty much every language's `==` operator acts differently and more sanely when compared to Java's.
Groovy had a very different initial design philosophy compared to Kotlin. The Groovy design philosophy was give Java developers a good highly-dynamic scripting language that still felt like Java but also made it more suitable for writing quick and dirty plugins, scripts and other extension bits to Java programs.
Kotlin is more in the "Java is great already, but has a lot of legacy issues, let's take all the stuff learned in the last two decades and make a Java++"
It's OK for a JVM language to define things differently to Java but still "feel like Java", but it should also have enough syntactic differences so programmers know it isn't Java. The Wikipedia page for Apache Groovy says "Most Java code is also syntactically valid Groovy, although semantics may be different" which isn't a good design.
Groovy had a very different initial design philosophy compared to Kotlin. The Groovy design philosophy was give Java developers a good highly-dynamic scripting language that still felt like Java but also made it more suitable for writing quick and dirty plugins, scripts and other extension bits to Java programs.
Kotlin is more in the "Java is great already, but has a lot of legacy issues, let's take all the stuff learned in the last two decades and make a Java++"