nodejs jsonwebtoken verify error with some tokens

Question

I've got a java service that generates json web tokens signed with RS256. Then a service in node verifies the tokens with the public key using the jsonwebtoken module.

The problem is that some tokens work and some do not. According to jwt.io every token is correct.

This an example code with a working one and a failing one

var sanitize = function(data){
  return data.replace(/\+/g, '-').replace(/\//g, '_').replace(/=*$/g, '')
}
var jwtGood = sanitize("eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiJ9.eyJ1c2VybmFtZSI6InBlbGF5by11c2VybmFtZTMiLCJlbWFpbCI6InBlbGF5by5yYW1vbisxMkBjbG91ZGRpc3RyaWN0LmNvbSIsInJvbGVzIjpbIlJPTEVfVVNFUiJdLCJpZCI6InVhb2V1YW9lb2FldTMiLCJpYXQiOjE0NTYxNDkwMjR9.tmvgtpuyuUiql2aYeR38kGTeQUwyb7XZr6Df2iv09_nxDn4HltHZm7Fvbj07ZQ5Hh_DmvlqZHz7EVSV6mERdjkohxf8tt9-J6NW_ftnUurCfLIzCcqEJ4xlKOzIgGsGrRd4ZUhw2hs4ZNTIscUb37csvKV-jPdSdQ-TxzuWZen4QnEUGvyg0VhdlU90TGZmpzobfpbHMQ3C0qhGRDMjghgej8zjWHbRDFRIGtAHLDbYVMiQRdI_GODIco2uSVh0_9PATSeRhFosHf3P3R4ohyBMrn9rxmBW4bQyFEMXWtsl4_PrKsdsaTtKjVQ2YuL5GjKQJqkWp6vx2vIxRabHz7w==");
var jwtBad  = sanitize("eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiJ9.eyJ1c2VybmFtZSI6InBlbGF5by11c2VybmFtZSIsImVtYWlsIjpudWxsLCJyb2xlcyI6WyJST0xFX1VTRVIiXSwiaWQiOm51bGwsImlhdCI6MTQ1NjMwMTUwN30=.X_vogPRHoE-ws2DxB8Q3wlm5JCQdOvuedhUC-1BlGa9qPdg5nmAGLoLuuGmQZ9r2yUD45OqKQ8_PVd05b0gQBhlIIWtQsXMSWypN6o43noZqMG6aM-GeAK-edDg2C7zw0yGQDD1BNLKBeWc8lNPzJAqQV0il_lg6bytIeN2LMAgxj78RZro3snkXN4woe6afCefW78z3KiOIQ2qI3pcA6Kf4j9NErHwfe9BP2dnV3mXTOZ8SIds_C9JWb7nt9o6Z4oCpskmXxhRCpP4ptTS0krGKfzfhYMKj2e7uOwS1pV4MdpQBeLlhZaGn3pmG5kwl3ZzEeIANfE7N8a9LofmFsQ==");

var jsonwebtoken = require('jsonwebtoken');
var fs = require('fs');

var pubKey = fs.readFileSync('public.pem');

console.log(jwtGood);
jsonwebtoken.verify(jwtGood, pubKey,{ algorithms: ['RS256'] },function(err, decoded){
  console.log(err,decoded);
});

console.log(jwtBad);
jsonwebtoken.verify(jwtBad, pubKey,{ algorithms: ['RS256'] },function(err, decoded){
  console.log(err,decoded);
});

The main difference just by looking at them is the "=" character at the end of the encoded payload. Working one payload ends in "MjR9." and failing one in "wN30=."

Removed the "=" by hand (as i did with the ending ones) but, according to jwt.io, without it the token is not verified.

Tried some more sanitize functions but they didn't work.

My guess is that there is a base64 encoding issue here but I can't find it.