No problem, glad to assist.
1) Unfortunately, sounds like the electrical panel was not wired by a competent electrician or a competent DIY'er. Per code, all Romex cables should have had the exterior white or yellow Romex insulation of the cable penetrating into the panel so that you can visually trace the corresponding conductors within the same NM Romex cable sheath.
2) Another method that can be used to confirm if a shared neutral conductor was installed is to eventually disconnect those neutrals one at a time and then use a continuity tester on the 2 kitchen circuits. If continuity is achieved on both circuit neutrals from any of the downstream receptacles, then this is wired as a Multi-Wired Branch Circuit (shared neutral circuit).
3) The tripping of the GFCI receptacles suggest a shared neutral circuit was installed. If confirmed that the circuit was wired as an MWBC then having 2 regular circuit breakers wired to 2 separate down stream GFCI receptacles along with LOAD side connections for non-GFCI receptacles will always trip an upstream GFCI receptacle. There are specific wiring methods used on an MWBC circuit with GFCI protection.
4) The GFCI is tripping because of one of the following:
A) An MWBC circuit was configured and LOAD side connection were terminated to each of the GFCI's
B) A direct short circuit exists causing the GFCI to trip
C) The incorrect neutral from another circuit was terminated.
5) If the 2 kitchen circuits were configured as a MWBC (shared neutral), this is a common issue as many electricians or DIY'ers do not install these circuits correctly (they use single pole breakers instead of double pole breaker types or the 2 single pole breaker don't contain a common trip handle tie. Most electricians do not label the conductors accordingly.
6) If confirmed the 2 circuits were wired as MWBC, these are the reasons I never recommend to wire any circuit as MWBC. They are nothing but a hassle to troubleshoot since they are seldom ever labeled. Unfortunately, the National Electrical Code only requires that an MWBC circuit resides within the same cable sheath or same conduit or the conductors be tie-wrapped together.
You are unable to even visually determine the cable sheath colors that enter into the panel. Multiple cables all bundled into the same NM Romex box connector. These are also indications of code violations and poor workmanship on whoever installed the branch circuit cables to the electrical panel.
7) In summary, I don't know if you have a MWBC (shared neutral circuit) or if a short is causing the tripping or if the wrong neutral was connected. Somehow, the single neutral or the 2 neutrals that feed these circuits need to be confirmed. For starters, an MWBC circuit needs to either be confirmed or ruled out.