RollingFileAppender issue

[Rayne1]

I'm reading the content of the log file line by line and generate web page like that:
if (SPIFFS.exists(FILENAME)) { File file = SPIFFS.open(FILENAME, "r"); String line; while (file.available()) { line = file.readStringUntil('\n'); website = website + " <div class=\"row\" style=\"padding-bottom:1em\">\n"; website = website + line; website = website + " </div>\n"; } file.close(); }

but finally for some rows I get three question marks in the end, the row also misses CR.
probably something is wrong with offset calculation or RollingFileAppender::end method.