This is easy to redo, in the default blend switch to logic editor, add 2 bricks and try link them. While the link works it flickers for me while I'm making it - flickering to a point outside the view. This seems to be because its using freed memory.

This would be because of a recent changes since it worked ok up-until recently.

==9621== Memcheck, a memory error detector
==9621== Copyright (C) 2002-2010, and GNU GPL'd, by Julian Seward et al.
==9621== Using Valgrind-3.6.1 and LibVEX; rerun with -h for copyright info
==9621== Command: /b/blender.bin
==9621==
==9621== Conditional jump or move depends on uninitialised value(s)
==9621== at 0x88DFD53: ??? (in /usr/lib/libnvidia-glcore.so.260.19.36)
==9621== by 0x800000003: ???
==9621== by 0x30000001F: ???
==9621== by 0x5B0000000000180: ???
==9621== by 0x400000003F: ???
==9621== by 0x1F0F030000001C: ???
==9621== Uninitialised value was created by a stack allocation
==9621== at 0x88DF570: ??? (in /usr/lib/libnvidia-glcore.so.260.19.36)
==9621==
==9621== Invalid read of size 4
==9621== at 0x91E938: ui_draw_linkline (interface.c:455)
==9621== by 0x91EA50: ui_draw_links (interface.c:476)
==9621== by 0x91FCD5: uiDrawBlock (interface.c:864)
==9621== by 0x7C11F5: logic_buttons_new (logic_window.c:4731)
==9621== by 0x7C1296: logic_buttons (logic_window.c:4757)
==9621== by 0x7C3F3B: logic_main_area_draw (space_logic.c:256)
==9621== by 0xA01C75: ED_region_do_draw (area.c:340)
==9621== by 0x753778: wm_method_draw_triple (wm_draw.c:597)
==9621== by 0x753E80: wm_draw_update (wm_draw.c:776)
==9621== by 0x752188: WM_main (wm.c:353)
==9621== by 0x751864: main (creator.c:1292)
==9621== Address 0xd758d80 is 640 bytes inside a block of size 1,080 free'd
==9621== at 0x4C2457C: free (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==9621== by 0xE4C81A: rem_memblock (mallocn.c:720)
==9621== by 0xE4C4D8: MEM_freeN (mallocn.c:637)
==9621== by 0x92278A: ui_free_but (interface.c:1907)
==9621== by 0x91EDC7: ui_but_update_from_old_block (interface.c:562)
==9621== by 0x91F2B0: uiEndBlock (interface.c:715)
==9621== by 0x7C11DF: logic_buttons_new (logic_window.c:4730)
==9621== by 0x7C1296: logic_buttons (logic_window.c:4757)
==9621== by 0x7C3F3B: logic_main_area_draw (space_logic.c:256)
==9621== by 0xA01C75: ED_region_do_draw (area.c:340)
==9621== by 0x753778: wm_method_draw_triple (wm_draw.c:597)
==9621== by 0x753E80: wm_draw_update (wm_draw.c:776)