java.io.IOException: Pushback buffer overflow

[SLNimesh]

Hello good people.
I'm new to this library, I have been trying to use your library for calendar sync between two/more booking sites.
Here is the problem:
When ever I try to read an .ics file it throws this exception,

java.io.IOException: Pushback buffer overflow
at java.base/java.io.PushbackReader.unread(PushbackReader.java:179) at net.fortuna.ical4j.data.UnfoldingReader.read(UnfoldingReader.java:187) at java.xml/com.sun.org.apache.xerces.internal.impl.XMLEntityScanner.load(XMLEntityScanner.java:1904) at java.xml/com.sun.org.apache.xerces.internal.impl.XMLEntityScanner.arrangeCapacity(XMLEntityScanner.java:1770) at java.xml/com.sun.org.apache.xerces.internal.impl.XMLEntityScanner.skipString(XMLEntityScanner.java:1808) ...

First I thought It was something wrong with the file and tried different ones. Finally I created an ics file using the library itself and tried to open it, but it failed all the time throwing the above exception.

Here is my ical4j.properties file
net.fortuna.ical4j.parser=net.fortuna.ical4j.data.HCalendarParserFactory net.fortuna.ical4j.timezone.registry=net.fortuna.ical4j.model.DefaultTimeZoneRegistryFactory net.fortuna.ical4j.timezone.update.enabled=true net.fortuna.ical4j.factory.decoder=net.fortuna.ical4j.util.DefaultDecoderFactory net.fortuna.ical4j.factory.encoder=net.fortuna.ical4j.util.DefaultEncoderFactory net.fortuna.ical4j.recur.maxincrementcount=1000 net.fortuna.ical4j.timezone.cache.impl=net.fortuna.ical4j.util.MapTimeZoneCache
ical4j.parsing.relaxed=true
ical4j.validation.relaxed=true

I couldn't find a solution online :( .
I'm using gradle in my project. compile group: 'org.mnode.ical4j', name: 'ical4j', version: '3.0.21'

        try {
            URL url = new URL("https://rocketcal.s3.eu-central-1.amazonaws.com/launches.ics");
            BufferedReader in = new BufferedReader(new InputStreamReader(url.openStream()));

//            PushbackReader pushbackReader = new PushbackReader(new BufferedReader(
//                    new InputStreamReader(oracle.openStream())
//            ),4);

//            String inputLine;
//            while ((inputLine = in.readLine()) != null) System.out.println(inputLine);

            CalendarBuilder calendarBuilder = new CalendarBuilder();
            Calendar calendar = calendarBuilder.build(in);
            in.close();
            //pushbackReader.close();
        } catch (IOException | ParserException e) {
            e.printStackTrace();
        }

Here is what I'm trying to do. I Even changed the PushBackBuffer size but it didn't help.

This can't be a problem with library, right? I found a similar issue here : https://sourceforge.net/p/ical4j/bugs/133/
So what am I missing here guys?
@pashazz @omarkilani @mernst @rfc2822
Please help this clueless soul.
Cheers : )