Very similar symptoms to bug 96425 , but different cause. Turns out to be a regression:

commit 44997fc0c1cc7f24216e3b1c5d954919df946ee5
Author: Kristian Høgsberg Kristensen <kristian.h.kristensen@intel.com>
Date:   Sun May 1 21:20:02 2016 -0700

    i965: Support textures with multiple planes
    
    Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

Trace with grass incorrectly rendered on the last frame:
https://drive.google.com/file/d/0Bz8fw_SGGDzsendNRDc2U1BFdk0/view?usp=sharing

This hack seems to be enough to unbreak it:

--- a/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
+++ b/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
@@ -911,8 +911,8 @@ brw_update_texture_surfaces(struct brw_context *brw)
    }
 
    if (fs) {
-      update_stage_texture_surfaces(brw, fs, &brw->wm.base, false, 1);
-      update_stage_texture_surfaces(brw, fs, &brw->wm.base, false, 2);
+      //update_stage_texture_surfaces(brw, fs, &brw->wm.base, false, 1);
+      //update_stage_texture_surfaces(brw, fs, &brw->wm.base, false, 2);
    }
 
    brw->ctx.NewDriverState |= BRW_NEW_SURFACES;