drreg error restoring tool value before app update for app instr that reads + writes

I hit a drreg bug where a tool has reserved a reg across an app instr that both reads and writes the reg: drreg was incorrectly restoring the tool value before writing out the new app value.

TAG  0x00007fd73015dc91
rcx is dead so reservation here inserts nothing.
 +0    m4 @0x0000000051bb9070  65 48 8b 0c 25 b0 00 mov    %gs:0x000000b0[8byte] -> %rcx
                               00 00
 +9    m4 @0x0000000051bb8f38  48 be 91 0c 01 00 0c mov    $0x2000e00c00010c91 -> %rsi
                               e0 00 20
 +19   m4 @0x0000000051bb8ff8  48 89 31             mov    %rsi -> (%rcx)[8byte]
 +22   m4 @0x0000000051bb9d48                       <label>
 +22   m4 @0x0000000051bb9f70  48 8d 49 08          lea    0x08(%rcx) -> %rcx
 +26   m4 @0x0000000051bb97d8  65 48 89 0c 25 b0 00 mov    %rcx -> %gs:0x000000b0[8byte]
                               00 00
 +35   L3                      48 89 d6             mov    %rdx -> %rsi
drreg preserving tool value:
 +38   m4 @0x0000000051bb5f58  65 48 89 0c 25 a0 00 mov    %rcx -> %gs:0x000000a0[8byte]
                               00 00
 +47   L3                      48 63 cb             movsxd %ebx -> %rcx
drreg updates app spill slot:
 +50   m4 @0x0000000051bb9ef8  65 48 89 0c 25 98 00 mov    %rcx -> %gs:0x00000098[8byte]
                               00 00
drreg restores tool value:
 +59   m4 @0x0000000051bba7f8  65 48 8b 0c 25 a0 00 mov    %gs:0x000000a0[8byte] -> %rcx
                               00 00
 +68   L3                      4c 29 fe             sub    %r15 %rsi -> %rsi
drreg preserving tool value:
 +71   m4 @0x0000000051bb6720  65 48 89 0c 25 a0 00 mov    %rcx -> %gs:0x000000a0[8byte]
                               00 00
drreg restores app value:
 +80   m4 @0x0000000051bb9310  65 48 8b 0c 25 98 00 mov    %gs:0x00000098[8byte] -> %rcx
                               00 00
 +89   L3                      48 c1 e1 04          shl    $0x0000000000000004 %rcx -> %rcx
out of order -- drreg restoring tool value should be after next line:
 +93   m4 @0x0000000051bb9238  65 48 8b 0c 25 a0 00 mov    %gs:0x000000a0[8byte] -> %rcx
                               00 00
drreg updating app spill slot:
 +102  m4 @0x0000000051bb90e8  65 48 89 0c 25 98 00 mov    %rcx -> %gs:0x00000098[8byte]
                               00 00
 +111  L3                      48 85 f6             test   %rsi %rsi