SSHFS mount to AWS Transfer for SFTP: cannot create regular file

I'm trying to setup an SSHFS mount point via Amazon's new service Transfer for SFTP. I can sftp into the endpoint just fine using sftp and can get/put files.

I can mount it using sshfs. I'm having problems where copying and moving files are showing errors. Whenever I do it creates 0 byte files. I have no problem using rm to remove them. What is also strange is that if I issue a 2nd cp command, it asks if I want to overwrite and then the file is there perfectly.

Here are some examples with SSHFS debug.

Note that I'm doing everything as root:

~$ sshfs -o workaround=all -o reconnect -o delay_connect -o sshfs_sync \
-o sync_readdir -o no_readahead -o debug -o noauto_cache \
-o cache=no user@my.endpoint:/my-bucket /mnt/s3

FUSE library version: 2.9.7
nullpath_ok: 1
nopath: 1
utime_omit_ok: 0
unique: 1, opcode: INIT (26), nodeid: 0, insize: 56, pid: 0
INIT: 7.26
flags=0x001ffffb
max_readahead=0x00020000
   INIT: 7.19
   flags=0x00000011
   max_readahead=0x00020000
   max_write=0x00020000
   max_background=0
   congestion_threshold=0
   unique: 1, success, outsize: 40
unique: 2, opcode: ACCESS (34), nodeid: 1, insize: 48, pid: 2285
access / 04
   unique: 2, success, outsize: 16
unique: 3, opcode: LOOKUP (1), nodeid: 1, insize: 47, pid: 2285
LOOKUP /.Trash
getattr /.Trash
X11 forwarding request failed on channel 0
   unique: 3, error: -2 (No such file or directory), outsize: 16
unique: 4, opcode: LOOKUP (1), nodeid: 1, insize: 52, pid: 2285
LOOKUP /.Trash-1000
getattr /.Trash-1000
   unique: 4, error: -2 (No such file or directory), outsize: 16

This does seem to successfully mount. I can ls and get a quick response.

As you can see I've turned off all caching and async via the options. I've also enabled all possible workarounds. I tried a bunch of different combinations of these options.

But when I try to cp anything:

~$ cp temp.txt /mnt/s3
cp: cannot create regular file './temp.txt': No such file or directory

unique: 86, opcode: GETATTR (3), nodeid: 1, insize: 56, pid: 18222
getattr /
   unique: 86, success, outsize: 120
unique: 87, opcode: LOOKUP (1), nodeid: 1, insize: 49, pid: 18222
LOOKUP /temp.txt
getattr /temp.txt
   unique: 87, error: -2 (No such file or directory), outsize: 16
unique: 88, opcode: LOOKUP (1), nodeid: 1, insize: 49, pid: 18222
LOOKUP /temp.txt
getattr /temp.txt
   unique: 88, error: -2 (No such file or directory), outsize: 16
unique: 89, opcode: CREATE (35), nodeid: 1, insize: 65, pid: 18222
create flags: 0x80c1 /temp.txt 0100644 umask=0022
   unique: 89, error: -2 (No such file or directory), outsize: 166

What is strange is that it does create a 0 byte file after a short delay:

~$ ls /mnt/s3
-rwxr--r-- 1 root root 0 Mar  7 12:19 temp.txt

If I issue a second cp it will overwrite without issue:

~$ cp temp.txt /mnt/s3
cp: overwrite './temp.txt'? y

unique: 65, opcode: GETATTR (3), nodeid: 1, insize: 56, pid: 18131
getattr /
   unique: 65, success, outsize: 120
unique: 66, opcode: LOOKUP (1), nodeid: 1, insize: 49, pid: 18131
LOOKUP /temp.txt
getattr /temp.txt
   NODEID: 6
   unique: 66, success, outsize: 144
unique: 67, opcode: LOOKUP (1), nodeid: 1, insize: 49, pid: 18131
LOOKUP /temp.txt
getattr /temp.txt
   NODEID: 6
   unique: 67, success, outsize: 144
unique: 68, opcode: OPEN (14), nodeid: 6, insize: 48, pid: 18131
open flags: 0x8001 /temp.txt
   open[139699381340688] flags: 0x8001 /temp.txt
   unique: 68, success, outsize: 32
unique: 69, opcode: SETATTR (4), nodeid: 6, insize: 128, pid: 18131
truncate /temp.txt 0
getattr /temp.txt
   unique: 69, success, outsize: 120
unique: 70, opcode: WRITE (16), nodeid: 6, insize: 539, pid: 18131
write[139699381340688] 459 bytes to 0 flags: 0x8001
   write[139699381340688] 459 bytes to 0
   unique: 70, success, outsize: 24
unique: 71, opcode: FLUSH (25), nodeid: 6, insize: 64, pid: 18131
flush[139699381340688]
   unique: 71, success, outsize: 16
unique: 72, opcode: RELEASE (18), nodeid: 6, insize: 64, pid: 0
release[139699381340688] flags: 0x8001
   unique: 72, success, outsize: 16

~$ ls /mnt/s3
-rwxr--r-- 1 root root 459 Mar  7 12:26 temp.txt

Using rm is no problem. Works as expected.

The mv command has the same issue as cp.

I do NOT want to use s3fs because it is unreliable so please don't offer as a solution.