Error: UID/seqno must be an integer, "*", or a range: NaN

[clochix]

Seen in the logs of a user when he tries to refresh its fastmail account:

Error: UID/seqno must be an integer, "*", or a range: NaN
    at validateUIDList (/usr/local/cozy/apps/emails/node_modules/imap/lib/Connection.js:1772:17)
    at ImapConnection.Connection._fetch (/usr/local/cozy/apps/emails/node_modules/imap/lib/Connection.js:760:3)
    at ImapConnection.Connection.fetch (/usr/local/cozy/apps/emails/node_modules/imap/lib/Connection.js:749:15)
    at ImapConnection.<anonymous> (/usr/local/cozy/apps/emails/build/server/imap/connection.js:161:20)
    at ImapConnection.Connection._resTagged (/usr/local/cozy/apps/emails/node_modules/imap/lib/Connection.js:1496:22)
    at Parser.<anonymous> (/usr/local/cozy/apps/emails/node_modules/imap/lib/Connection.js:173:10)
    at emitOne (events.js:77:13)
    at Parser.emit (events.js:169:7)
    at Parser._resTagged (/usr/local/cozy/apps/emails/node_modules/imap/lib/Parser.js:174:10)
    at Parser._parse (/usr/local/cozy/apps/emails/node_modules/imap/lib/Parser.js:138:16)