diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.cpp
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.cpp
@@ -798,6 +798,11 @@
   if (!reg_info)
     return;
 
+  // When vg is written it is automatically made invalid. Writing vg will also
+  // change svg if we're in streaming mode, so we must fetch the latest value
+  // from the remote.
+  SetRegisterIsValid(reg_info, false);
+
   uint64_t fail_value = LLDB_INVALID_ADDRESS;
   uint32_t svg_reg_num = reg_info->kinds[eRegisterKindLLDB];
   uint64_t svg_reg_value = ReadRegisterAsUnsigned(svg_reg_num, fail_value);
diff --git a/lldb/test/API/commands/register/register/aarch64_za_reg/za_dynamic_resize/TestZAThreadedDynamic.py b/lldb/test/API/commands/register/register/aarch64_za_reg/za_dynamic_resize/TestZAThreadedDynamic.py
--- a/lldb/test/API/commands/register/register/aarch64_za_reg/za_dynamic_resize/TestZAThreadedDynamic.py
+++ b/lldb/test/API/commands/register/register/aarch64_za_reg/za_dynamic_resize/TestZAThreadedDynamic.py
@@ -125,11 +125,13 @@
                 self.runCmd("thread select %d" % (idx + 1))
                 self.check_za_register(4, 2)
                 self.runCmd("register write vg 2")
+                self.check_disabled_za_register(2)
 
             elif stopped_at_line_number == thY_break_line1:
                 self.runCmd("thread select %d" % (idx + 1))
                 self.check_za_register(2, 3)
                 self.runCmd("register write vg 4")
+                self.check_disabled_za_register(4)
 
         self.runCmd("thread continue 2")
         self.runCmd("thread continue 3")