fix: bbb splitting dupe issue (#1908)

* fix bbb group splitting issues

* address feedback

.github/copilot-instructions.md

@@ -0,0 +1,29 @@
+# GitHub Copilot Instructions
+
+ * c++20 standard, please use the latest features except NO modules.
+   * use `.contains` for searching in associative containers
+ * use const as much as possible.  If it can be const, it should be made const
+ * DO NOT USE const_cast EVER.
+ * use `cstdint` bitwidth types ALWAYS for integral types.
+ * NEVER use std::wstring. If wide strings are necessary, use std::u16string with conversion utilties in GeneralUtils.h.
+ * Functions are ALWAYS PascalCase.
+ * local variables are camelCase
+ * NEVER use snake case
+ * indentation is TABS, not SPACES.
+ * TABS are 4 spaces by default
+ * Use trailing braces ALWAYS
+ * global variables are prefixed with `g_`
+ * if global variables or functions are needed, they should be located in an anonymous namespace
+ * Use `GeneralUtils::TryParse` for ANY parsing of strings to integrals.
+ * Use brace initialization when possible.
+ * ALWAYS default initialize variables.
+ * Pointers should be avoided unless necessary. Use references when the pointer has been checked and should not be null
+ * headers should be as compact as possible. Do NOT include extra data that isnt needed.
+ * Remember to include logs (LOG macro uses printf style logging) while putting verbose logs under LOG_DEBUG.
+ * NEVER USE `RakNet::BitStream::ReadBit`
+ * NEVER assume pointers are good, always check if they are null. Once a pointer is checked and is known to be non-null, further accesses no longer need checking
+ * Be wary of TOCTOU. Prevent all possible issues relating to TOCTOU.
+ * new memory allocations should never be used unless absolutely necessary.
+    * new for reconstruction of objects is allowed
+ * Prefer following the format of the file over correct formatting.  Consistency over correctness.
+ * When using auto, ALWAYS put a * for pointers.