Tomcat9 log that I have no idea what to do with

I saw the following in tomcat logs

09-Sep-2019 21:04:04.268 SEVERE [https-jsse-nio2-8443-exec-13] org.apache.coyote.AbstractProtocol$ConnectionHandler.process Error reading request, ignored java.lang.NullPointerException

I saw that the fix for the above is to use NIO2 but I already use it.

08-Sep-2019 22:32:14.979 INFO [https-jsse-nio2-8443-exec-16] org.apache.coyote.http11.Http11Processor.service Error parsing HTTP request header Note: further occurrences of HTTP request parsing errors will be logged at DEBUG level. java.lang.IllegalArgumentException: Invalid character found in method name. HTTP method names must be tokens

I read that it's something related to http/https. I'm calling tomcat with https, port 8443 and both clients (mobile app and windows application) are calling it with https... what am I missing?

07-Sep-2019 20:50:49.005 INFO [https-jsse-nio2-8443-exec-18] org.apache.tomcat.util.http.Parameters.processParameters Invalid chunk starting at byte [48] and ending at byte [49] with a value of [=] ignored

That I don't even know what it means and why.

Let me know if more info is needed, thanks a lot.

log from undeploy/deploy war if relevant

05-Sep-2019 16:37:59.517 INFO [https-jsse-nio2-8443-exec-8] org.apache.catalina.startup.HostConfig.undeploy Undeploying context [/app] 05-Sep-2019 16:38:14.028 INFO [https-jsse-nio2-8443-exec-1] org.apache.catalina.startup.HostConfig.deployWAR Deploying web application archive [/opt/tomcat/apache-tomcat-9.0.24/webapps/app.war] 05-Sep-2019 16:38:17.971 INFO [https-jsse-nio2-8443-exec-1] org.apache.jasper.servlet.TldScanner.scanJars At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger fo$05-Sep-2019 16:38:18.011 INFO [https-jsse-nio2-8443-exec-1] org.apache.catalina.startup.HostConfig.deployWAR Deployment of web application archive [/opt/tomcat/apache-tomcat-9.0.24/webapps/app.war] has$SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder". SLF4J: Defaulting to no-operation (NOP) logger implementation SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details. 05-Sep-2019 16:38:37.418 WARNING [grpc-default-executor-0] io.grpc.netty.shaded.io.netty.util.internal.MacAddressUtil.defaultMachineId Failed to find a usable hardware address from the network interfaces; u$