In short: no. What you're seeing is that a random action (in this case the login) is triggering an out of memory error. These occur when the JVM (the java virtual machine, which hosts the Mendix runtime) tries to do 'something' and there's no available memory.
This 'something' does not necessarily take a lot of memory. It just happens to trigger it. In other words, imagine the JVM as a big bucket of water. Your login action was the drop that caused it to overflow, but it was probably not what filled it up.
Trying to figure out out of memory errors is a whole science in itself. That being said, they are often (but not always) caused by 'expensive' computations such as batch jobs, scheduled events or Microflows that operate on a large amount of data. You can investigate this by checking the running requests and try to detect a pattern. Alternatively, checking your graphs (trends) in the cloud portal if you're running there could help correlate the errors and events.
Seems like that on login of MxAdm a select is done on system$clustermanager, which has a huge impact on the memory, causing a heap space. Is there a login microflow or hopepage which is doing something special?