In general, I agree that the application should not crash like that. However, even more important is that the log file is displayed correctly and no log entries are 'hidden' or 'lost'. In this case, invalid JSON was detected. LogViewPlus tried to recover by reading the next log line and combining it with the (so far) invalid JSON. When this failed, it became impossible for the application to display the file accurately. In this case, I believe a crash is appropriate.
In the next version of LogViewPlus, we plan to add an option to the JSON parser which allows for 'single line' JSON. If the JSON log entry should exist on a signal line, then the scanning process can be skipped. The JSON is still invalid, but the parser we are introducing in this release should be significantly better at handling invalid JSON. Even if the line cannot be parsed, it can still be combined with another line so that processing can continue. I believe your JSON object is on a single line, so this kind of logic would help.
To store a JSON object in a property, define your conversion specifier in the usual way:
{
"message":"%m"
}
This definition can process messages like:
{
"message": "Application initializing."
}
Or:
{
"message": {
"value1" : "Hello",
"value2" : "World",
}
}
It is necessary for the message field to be a string in the parser configuration (where the conversion specifier is defined). However, the field value can be any JSON type.
The above JSON will be displayed in LogViewPlus as:

Hope that helps,
Toby