I did an apitrace and I have some gdb output:

p ctx->Texture.Unit[0]
$6 = {Enabled = 0, EnvMode = 8448, EnvColor = {0, 0, 0, 0}, 
  EnvColorUnclamped = {0, 0, 0, 0}, GenS = {Mode = 9216, _ModeBit = 4, 
    ObjectPlane = {1, 0, 0, 0}, EyePlane = {1, 0, 0, 0}}, GenT = {Mode = 9216, 
    _ModeBit = 4, ObjectPlane = {0, 1, 0, 0}, EyePlane = {0, 1, 0, 0}}, 
  GenR = {Mode = 9216, _ModeBit = 4, ObjectPlane = {0, 0, 0, 0}, EyePlane = {
      0, 0, 0, 0}}, GenQ = {Mode = 9216, _ModeBit = 4, ObjectPlane = {0, 0, 0, 
      0}, EyePlane = {0, 0, 0, 0}}, TexGenEnabled = 0, _GenFlags = 0, 
  LodBias = 0, _BoundTextures = 3200, Sampler = 0x0, Combine = {
    ModeRGB = 8448, ModeA = 8448, SourceRGB = {5890, 34168, 34166, 34166}, 
    SourceA = {5890, 34168, 34166, 34166}, OperandRGB = {768, 768, 770, 770}, 
    OperandA = {770, 770, 770, 770}, ScaleShiftRGB = 0, ScaleShiftA = 0, 
    _NumArgsRGB = 2, _NumArgsA = 2}, _EnvMode = {ModeRGB = 8448, ModeA = 8448, 
    SourceRGB = {5890, 34168, 34166, 34166}, SourceA = {5890, 34168, 34166, 
      34166}, OperandRGB = {768, 768, 770, 770}, OperandA = {770, 770, 770, 
      770}, ScaleShiftRGB = 0, ScaleShiftA = 0, _NumArgsRGB = 2, 
    _NumArgsA = 2}, _CurrentCombine = 0x56c378b8, CurrentTex = {0x56e581d0, 
    0x56e7a920, 0x56e5a670, 0x56e5c220, 0x56d86280, 0x56d4d110, 0x56daa460, 
    0x5b81ab00, 0x56da97a0, 0x56e63b10, 0x5b81e790, 0x56e6e940}, 
  _Current = 0x0, _CurrentCombinePacked = {ModeRGB = 1, ModeA = 1, 
    ScaleShiftRGB = 0, ScaleShiftA = 0, NumArgsRGB = 2, NumArgsA = 2, 
    ArgsRGB = {{Source = 8 '\b', Operand = 0 '\000'}, {Source = 9 '\t', 
        Operand = 0 '\000'}, {Source = 0 '\000', Operand = 0 '\000'}, {
        Source = 0 '\000', Operand = 0 '\000'}}, ArgsA = {{Source = 8 '\b', 
---Type <return> to continue, or q <return> to quit---
        Operand = 2 '\002'}, {Source = 9 '\t', Operand = 2 '\002'}, {
        Source = 0 '\000', Operand = 0 '\000'}, {Source = 0 '\000', 
        Operand = 0 '\000'}}}}
(gdb) p ctx->Texture.Unit[0]._Current
$7 = (struct gl_texture_object *) 0x0
(gdb) bt
#0  st_update_single_texture (st=0x56d57ca0, sampler_view=0xffffc8a4, 
    texUnit=0, glsl130_or_later=false, ignore_srgb_decode=false)
    at ../../../../src/mesa/state_tracker/st_atom_texture.c:76
#1  0xf6a94eef in update_textures (st=0x56d57ca0, 
    shader_stage=PIPE_SHADER_FRAGMENT, prog=0x56ce1bb8, 
    sampler_views=0x56d595fc, out_num_textures=0x56d59880)
    at ../../../../src/mesa/state_tracker/st_atom_texture.c:157
#2  0xf6a951ba in st_update_fragment_textures (st=0x56d57ca0)
    at ../../../../src/mesa/state_tracker/st_atom_texture.c:241
#3  0xf6a90732 in st_validate_state (st=<optimized out>, 
    pipeline=ST_PIPELINE_RENDER)
    at ../../../../src/mesa/state_tracker/st_atom.c:251
#4  0xf6aaf675 in st_draw_vbo (ctx=0x56c34f60, prims=0xffffca4c, nr_prims=1, 
    ib=0xffffca3c, index_bounds_valid=0 '\000', min_index=<optimized out>, 
    max_index=<optimized out>, tfb_vertcount=0x0, stream=0, indirect=0x0)
    at ../../../../src/mesa/state_tracker/st_draw.c:122
#5  0xf6a71f7c in vbo_validated_drawrangeelements (ctx=0x56c34f60, mode=4, 
    index_bounds_valid=<optimized out>, start=0, end=4294967295, count=1074, 
    type=5123, indices=0x96b1db20, basevertex=0, numInstances=1, 
    baseInstance=0) at ../../../../src/mesa/vbo/vbo_exec_array.c:925
#6  0xf6a72609 in vbo_exec_DrawElements (mode=4, count=1074, type=5123, 
    indices=0x96b1db20) at ../../../../src/mesa/vbo/vbo_exec_array.c:1075
#7  0x56668f42 in retrace_glDrawElements (call=...)
---Type <return> to continue, or q <return> to quit---
    at /home/andreas/Develop/apitrace/build32/retrace/glretrace_gl.cpp:10346
#8  0x56580f39 in retrace::retraceCall (call=<optimized out>)
    at /home/andreas/Develop/apitrace/retrace/retrace_main.cpp:279
#9  0x5657a99b in retrace::mainLoop ()
    at /home/andreas/Develop/apitrace/retrace/retrace_main.cpp:606
#10 main (argc=<optimized out>, argv=<optimized out>)
    at /home/andreas/Develop/apitrace/retrace/retrace_main.cpp:1090

fixed in current git