When trying to checkout a HG repository via https, the process aborts with an internal server error. I'm running the most recent stable version of phabricator as of today. The error log is added below. In case you need any more information please let me know.
[Mon Aug 29 09:17:49.678650 2016] [:error] [pid 21992] [client XXX.XXX.XXX.XX7:60812] PHP Fatal error: String size overflow in /var/www/phabricator/libphutil/src/future/exec/ExecFuture.php on line 738 [Mon Aug 29 09:17:49.678894 2016] [:error] [pid 21992] [client XXX.XXX.XXX.XX7:60812] >>> UNRECOVERABLE FATAL ERROR <<<\n\nString size overflow\n\n/var/www/phabricator/libphutil/src/future/exec/ExecFuture.php:738\n\n\n\xe2\x94\xbb\xe2\x94\x81\xe2\x94\xbb \xef\xb8\xb5 \xc2\xaf\\_(\xe3\x83\x84)_/\xc2\xaf \xef\xb8\xb5 \xe2\x94\xbb\xe2\x94\x81\xe2\x94\xbb [Mon Aug 29 09:22:43.079010 2016] [:error] [pid 21992] [client XXX.XXX.XX.XX6:56624] PHP Fatal error: String size overflow in /var/www/phabricator/libphutil/src/future/exec/ExecFuture.php on line 738 [Mon Aug 29 09:22:43.079187 2016] [:error] [pid 21992] [client XXX.XXX.XX.XX6:56624] >>> UNRECOVERABLE FATAL ERROR <<<\n\nString size overflow\n\n/var/www/phabricator/libphutil/src/future/exec/ExecFuture.php:738\n\n\n\xe2\x94\xbb\xe2\x94\x81\xe2\x94\xbb \xef\xb8\xb5 \xc2\xaf\\_(\xe3\x83\x84)_/\xc2\xaf \xef\xb8\xb5 \xe2\x94\xbb\xe2\x94\x81\xe2\x94\xbb [Mon Aug 29 09:24:42.267258 2016] [:error] [pid 32587] [client XXX.XXX.XX.XX6:56634] PHP Fatal error: String size overflow in /var/www/phabricator/libphutil/src/future/exec/ExecFuture.php on line 738 [Mon Aug 29 09:24:42.267461 2016] [:error] [pid 32587] [client XXX.XXX.XX.XX6:56634] >>> UNRECOVERABLE FATAL ERROR <<<\n\nString size overflow\n\n/var/www/phabricator/libphutil/src/future/exec/ExecFuture.php:738\n\n\n\xe2\x94\xbb\xe2\x94\x81\xe2\x94\xbb \xef\xb8\xb5 \xc2\xaf\\_(\xe3\x83\x84)_/\xc2\xaf \xef\xb8\xb5 \xe2\x94\xbb\xe2\x94\x81\xe2\x94\xbb [Mon Aug 29 09:26:30.819787 2016] [:error] [pid 22281] [client XXX.XXX.XX.XX6:56638] PHP Fatal error: String size overflow in /var/www/phabricator/libphutil/src/future/exec/ExecFuture.php on line 738 [Mon Aug 29 09:26:30.819976 2016] [:error] [pid 22281] [client XXX.XXX.XX.XX6:56638] >>> UNRECOVERABLE FATAL ERROR <<<\n\nString size overflow\n\n/var/www/phabricator/libphutil/src/future/exec/ExecFuture.php:738\n\n\n\xe2\x94\xbb\xe2\x94\x81\xe2\x94\xbb \xef\xb8\xb5 \xc2\xaf\\_(\xe3\x83\x84)_/\xc2\xaf \xef\xb8\xb5 \xe2\x94\xbb\xe2\x94\x81\xe2\x94\xbb [Mon Aug 29 09:28:19.719739 2016] [:error] [pid 999] [client XXX.XXX.XX.XX6:56654] PHP Fatal error: String size overflow in /var/www/phabricator/libphutil/src/future/exec/ExecFuture.php on line 738 [Mon Aug 29 09:28:19.719938 2016] [:error] [pid 999] [client XXX.XXX.XX.XX6:56654] >>> UNRECOVERABLE FATAL ERROR <<<\n\nString size overflow\n\n/var/www/phabricator/libphutil/src/future/exec/ExecFuture.php:738\n\n\n\xe2\x94\xbb\xe2\x94\x81\xe2\x94\xbb \xef\xb8\xb5 \xc2\xaf\\_(\xe3\x83\x84)_/\xc2\xaf \xef\xb8\xb5 \xe2\x94\xbb\xe2\x94\x81\xe2\x94\xbb [Mon Aug 29 09:29:37.065638 2016] [:error] [pid 22281] [client XXX.XXX.XX.X8:63733] PHP Fatal error: String size overflow in /var/www/phabricator/libphutil/src/future/exec/ExecFuture.php on line 738 [Mon Aug 29 09:29:37.065827 2016] [:error] [pid 22281] [client XXX.XXX.XX.X8:63733] >>> UNRECOVERABLE FATAL ERROR <<<\n\nString size overflow\n\n/var/www/phabricator/libphutil/src/future/exec/ExecFuture.php:738\n\n\n\xe2\x94\xbb\xe2\x94\x81\xe2\x94\xbb \xef\xb8\xb5 \xc2\xaf\\_(\xe3\x83\x84)_/\xc2\xaf \xef\xb8\xb5 \xe2\x94\xbb\xe2\x94\x81\xe2\x94\xbb